Growth Hormone Does Not Prevent Loss of Muscle Strength

As you age, expect to lose muscle fibers and strength unless you exercise. A study from the University of Florida in Gainesville shows that a program of exercise training later in life helps aging rats to reverse this age-related loss of muscle size and strength (American Journal of Physiology: Regulatory, Integrative and Comparative Physiology, November 14, 2007). The study also showed that short-term administration of growth hormone late in life does not prevent loss of muscle strength. Previous studies show that it may help people get rid of fat.

At this time, there is not enough evidence for an older person to take growth hormone to improve muscle strength, and there is no long-term data on safety. Sudden deaths reported in athletes who have taken growth hormone are probably due to the effect of enlarging the heart muscle without also adequately enlarging the blood supply. The larger heart requires more blood and cannot meet its needs for oxygen, so it starts to beat irregularly. More on growth hormone; growth hormone releasers; growth hormone and aging

Job Fatigue? Carb Snacks Can Help

If you have a physically demanding job that keeps you moving all day, you may have greater endurance if you eat small snacks throughout the day instead of having a single large meal at lunchtime. Researchers at the University of Montana in Missoula showed that snacking on carbohydrates may prolong your endurance during a long day of continuous movement. They asked men and women to exercise intermittently for ten hours. Each hour, they performed nine minutes of upper-body weight lifting, 19 minutes of cycling, and 20 minutes of walking on a treadmill, with a one-minute rest between each exercise. This was followed by a 10-minute rest and feeding period. Those who took carbohydrates every hour were able to keep more sugar (glycogen) in their muscles, and were able to exercise longer without feeling tired. Journal reference

When you exercise, your muscles get their energy from muscle sugar and fat stored in muscles, sugar and fat from the bloodstream, and to a lesser degree from protein. When your muscles run out of their stored sugar, they require more oxygen to burn food for energy. This can make your muscles feel tired and be more difficult to coordinate. Eating any source of sugar or carbohydrates during exercise preserves muscle sugar and increases endurance. More

Longevity Linked More to Fitness than Weight

Being in shape helps to prolong your life, even if you are overweight and even if you store fat primarily in your belly, which is a major risk factor for diabetes, heart attacks, and probably certain types of cancers (JAMA, December 5, 2007). As people age, most gain weight and become progressively less active. Researchers at the University of South Carolina in Columbia showed that a person's fitness level was a far stronger predictor of premature death than body fat. Those who were fit suffered less than half the death rate of those who were out of shape. They also showed that those who store fat primarily on their bellies are at significantly greater risk for dying early and that people with abdominal obesity who exercise are far less likely to die early than those who did not exercise.

The authors describe fitness as walking briskly at least five days a week. Abdominal obesity is defined as having a waist circumference over 40 inches for men or 35 inches for women. In this study, the least fit 20 percent had a death rate twice as high as people who did 30 minutes of walking five days a week. Those who were more fit had an even lower death rate. Furthermore, higher levels of fitness were inversely related to all causes of death in both the normal-weight and overweight groups.

Intestinal Bacteria May Cause Weight Gain

Why are some people skinny, even though they eat large amounts of food, while others become fat? Jeffery Gordon of Washington University in St. Louis thinks it's because some people have types of bacteria that cause them to absorb more calories from their food.

You have two absorption systems in your body. You absorb most of your food as it passes through your small intestines. Food that is not absorbed in the small intestine goes to your colon. The colon contains a huge colony of bacteria that work to ferment undigested carbohydrates such as soluble fiber into short chain fatty acids and simple sugars that can then be absorbed through the colon walls into the bloodstream. Most people get about ten percent of their total calories from food absorbed through their colons.

Animal studies lead us to the next step. The dominant bacteria in the gut of obese mice are Firmicutes, types of bacteria that have more genes for breaking down the complex starches and fiber. Mice who are thin have more Bacteroidetes in their guts, and these bacteria are not as efficient in breaking down fiber and complex carbohydrates. Transplanting Firmicutes bacteria into the guts of lean mice made them fat.

These researchers also found that fat humans had far more Firmicutes bacteria than thinner ones. They then asked their overweight subjects to go on a low-fat, low-refined- carbohydrate diet for one year. As they lost weight, their bacteria changed to predominantly Bacteroidetes.

Today you may be able to lose weight by changing the composition of your diet in a way that changes the bacteria in your gut so you absorb fewer calories. In the future, you may be able to get a pill that contain primarily Bacteroidetes bacteria, take it daily and watch the pounds melt off because of the change in intestinal bacteria. Fitness, Nutrition and Health newsletter

Clementines: Healthful Snacking and More

Clementines are the small citrus in boxes or mesh bags that appear in markets during the winter months. This year's crop is tasty, juicy and plentiful (prices are low!).
They're great for snacking, dessert or in fruit salads. Clementines also make a wonderful addition to almost any green salad. Or try Diana's Recipes Using Clementines.

In Canada and perhaps elsewhere clementines may be called mandarins. Technically clementines are a cross between mandarins (Citrus reticulata) and Seville oranges (Citrus auratium). Recipes using clementines can be made with any of the tangerine-sized citrus or with oranges sections cut into bite-size pieces.

To prepare clementines for salads, just peel and section. If they are large or you want more flavor from the juice in your salad, cut the peeled fruit in half cross-wise before you separate the sections.

Look for boxes of small, firm fruit. I find that the smaller clementines often have the best flavor, although they may be more difficult to peel. If you get a box with poor flavor, look for another "brand" (from the box labels) and try again. They come from Spain, Morocco, South America and various other countries; I haven't found any reliable way to tell which will taste best. If you can find the ones from California (often labelled "California Cuties", in mesh bags), they seem to be consistently good.

Just a few years ago no one had heard of clementines; now they're everywhere and they sell like hotcakes. I hope that food marketers will take note that SHOPPERS WILL BUY healthful foods if they are tasty, attractively packaged and reasonably priced. Vote with your pocketbook; buy lots and enjoy!

Lactose Intolerance: How to Eat Healthfully

Fifty percent of North Americans are lactose intolerant. They lack the enzyme to split the double sugar, lactose, found in milk and other dairy products. Since you can only absorb single sugars, if you can't split the double sugar, it passes to your large intestine where it is attacked by bacteria and fermented, causing gas and cramping. Some people deal with this by adding the lactase enzyme to their diet.

You can eliminate all dairy products and still have a perfectly healthful diet. Yes, milk is a good source of calcium, vitamin D, protein and other nutrients, but it is far from essential. You can get all the calcium you need from a variety of other foods.

Many doctors, dieticians and vegetarians oppose the use of dairy products, and back their position with extensive research data. Check the Physicians Committee for Responsible Nutrition web site, www.pcrm.org, for some interesting articles and journal references.

You can get plenty of calcium in your diet if you include lots of leafy green vegetables, a wide variety of beans and whole grains, and perhaps fortified products such as soy milk, cereals and juices. The RDA for calcium ranges from 800mg for young children to 1500mg for older people and pregnant or nursing women. If you're not sure you are getting that amount in your diet, it won't hurt to take a calcium supplement.

Here's the calcium content of some typical beans, vegetables and fruits (Portion size is 1 cup, cooked, unless otherwise noted):

Black beans - 103 mg
Chick peas - 80 mg
Pinto beans - 82 mg
Soybeans - 175 mg
White beans - 161 mg
Broccoli - 94 mg
Collard greens - 358 mg
Spinach - 244 mg
Swiss chard - 102 mg
Dried figs (10)- 269 mg
Orange (1) - 56 mg
Raisins - (2/3 cup) - 53 mg
Tofu (½ cup) - 258 mg.)

Wound Healing Time Increases with Age; Exercise Can Help

Animal studies suggest that exercise may be even more important for older people than for younger ones. A report from the University of Illinois at Urbana-Champaign shows that exercise significantly decreased wound size and increased healing rate in older mice. However, exercise had little effect on the rate of wound healing in young mice. (American Journal of Physiology - Regulatory, Integrative and Comparative Physiology, November 14, 2007).

Mice ran on a treadmill at moderate intensity for 30 minutes a day for eight days. They then were given four full- thickness skin wounds and the rate of wound healing was checked daily for 10 days. Compared to age-matched non- exercising mice, the older exercisers healed faster.

The leading theory is that aging delays wound healing presumably because aging causes your body to produce more free radicals that damage the genetic material in cells. After you eat, food travels into mitochondria, small areas in cells that turn food into energy. They do this by removing electrons and hydrogen from nutrients. The electrons then attach to oxygen to form free radicals that stick to and damage the genetic material DNA in cells. This can delay healing and presumably even shorten life. Exercise causes the mitochondria to turn food into energy without producing as many free radicals, and therefore could hasten healing from any type of injury or illness. More on mitochondria and aging

Stretching: Know When, How and Why

Stretching the leg muscles improves muscle flexibility and strength, running speed, and jumping distance, according to a study from Louisiana State University. Stretching elongates muscles and tendons. Longer tendons allow muscles to exert a greater torque on the joint to exert more power to help you lift heavier, jump higher and run faster.

However, other studies show that you should not stretch before a competition involving speed and strength. The longer the athletes stretched, the weaker they became. Prolonged stretching fatigues muscle fibers so that they contract with reduced force. Do slow deliberate stretches lasting a few seconds to several seconds, rather than rapid hard pulls on your muscles that can tear them. Stretching cold muscles can also tear them and increase risk for injury. Warm up before stretching or stretch after your workout, but realize that prolonged stretching before a competition can harm performance. Journal references; more on stretching

Athletes Harm Others with Performance Enhancing Drugs

Some people think that we should let athletes take performance-enhancing drugs because they think that these athletes can only harm themselves and do not harm others. We already know that anabolic steroids can cause liver damage, heart attacks and strokes, and that growth hormone causes heart attacks by causing the heart muscle to outgrow its blood supply. Now a two-year study of former East German athletes shows that athletes who take these drugs can harm their children.

In the 1970s and 80s, almost all government sponsored East German athletes were forced to take anabolic steroids and other performance-enhancing drugs. A study of 69 children of 52 of these athletes showed that seven had birth defects and four were mentally retarded, an unusually high incidence for a group of this size. More than 25 percent had allergies and 23 percent had asthma. The women suffered 32 times the normal incidence of miscarriage and stillbirth, 25 percent suffered cancer and 61 percent had therapy for mental disorders. The study was conducted by Dr. Giselher Spitzer at Humbolt University in Germany.

Many people are not aware that at this time, there is no test to catch athletes who take growth hormone. The winner of the 2006 Tour de France and the leader of the 2007 tour were disqualified for allegedly taking performance-enhancing drugs. This was just the tip of the iceberg. Martial Saugy, director of the Swiss Laboratory for Analysis of Doping in Lausanne, Switzerland, told a Belgian newspaper that 47 of 189 riders raced on blood transfusions or EPO in the 2007 Tour de France. The tests did not meet standards necessary to disqualify the riders. He also suspects that the riders also took testosterone and growth hormone. More

Mental Fatigue from Low Blood Sugar Levels

Exercisers and athletes can expect to feel fatigued when their blood sugar levels drop. Researchers at Loughborough University, UK showed that athletes who did not take sugar during soccer competition lasting 90 minutes felt more tired, had less competitive desire, and had far lower blood sugar levels than athletes who took a sugared drink every 15 minutes during their game.

Your brain gets more than 98 percent of its energy from sugar in the bloodstream. However there is only enough sugar in the bloodstream to last about three minutes. The liver must constantly release sugar into the bloodstream, but there is only enough sugar in the liver to last eight hours during rest and far less than that during exercise. So athletes who do not take a source of sugar during events lasting more than an hour can suffer the psychological effects of low blood sugar levels what include a mental feeling of fatigue and lowered competitive desire.

In another study, researchers at the University of Waterloo in Canada showed that taking sugar 30 minutes after starting to cycle and every 15 minutes afterwards increases strength, speed and endurance when exercising fairly intensely at 60 percent of maximal oxygen uptake. Muscles burn carbohydrates, fats, and protein for energy. Carbohydrates (sugars) require the least amount of oxygen for conversion to energy, which allows you to move faster with less effort. Athletes use sugared drinks, power bars or candy bars, concentrated sugared gels, cookies and almost any other source of carbohydrates during prolonged competition. It is possible to take in too much sugar and get a high rise in blood sugar if you are not exercising intensely, but this is rarely a concern for competing athletes. Competition takes great concentration, and eating and drinking are distractions that most athletes limit as much as possible. Journal references

Angioplasty Patients Can and Should Exercise

If you have had angioplasty and your doctor does not already have you in as supervised exercise program, ask when you can start. In one study from Bern, Switzerland, researchers showed that a three-month exercise program can increase blood flow to the heart in people who already have their coronary arteries blocked by plaques (European Journal of Cardiovascular Prevention and Rehabilitation, April 2007). The study participants were selected from patients who had stents inserted to widen blockages in their coronary arteries. The longer and harder the subjects were able to exercise, the greater the increase in blood flow.

The blood flow to the heart muscle comes primarily from arteries on the outside surface of the heart. Chest pain with exercise is usually caused by narrowing of these arteries, which prevents adequate amounts of blood to flow to the heart muscle. The heart muscle then suffers from lack of oxygen and hurts. A heart attack occurs when plaques that coat the inner lining of arteries leading to the heart break off and travel down the ever- narrowing artery until they completely obstruct the flow of blood to a part of the heart muscle. Then part of the heart muscle that is deprived of oxygen dies and a person suffers a heart attack. People with damaged coronary arteries are at higher risk for heart attacks during exercise, so the study participants were checked for blood flow to the heart before and after the program, and were monitored during exercise by professional personnel.

Smarter Baseball Players Live Longer

Smarter baseball players live longer, according to researchers at the Department of Economics at Shippensburg University in Pennsylvania. The authors collected data on players who were born between 1945 and 1964 and found that the death rate for players who attended only high school was almost twice as high as those who went to college. They also found what high body fat levels were associated with premature death. The study was published in the journal Death Studies.

The good news for all athletes is that the baseball players had only 31 percent of the death rate of the general population. The lower death rate in the more highly educated players is probably due to their increased awareness of life style factors linked to premature death, such as smoking, promiscuity, obesity, eating a high-fat, high-refined carbohydrate diet that is low in vegetables, and so forth.

Small Lifestyle Changes Combat Obesity in Children and their Families

Pediatricians at the University of Colorado at Denver have shown that very small changes in lifestyle can help stem the epidemic of obesity in North American children. Families of overweight children, seven to fourteen years of age, were asked to make two lifestyle changes: 1) to walk an additional 2000 steps per day, as measured by pedometers, and 2) to eliminate 100 calories per day by replacing a source of dietary sugar with a non-caloric beverage or sweetener. At the end of the six-month trial, most of the children had lost weight and the parents had no significant weight gain. Journal reference

Obesity comes from eating too much and exercising too little. It is associated with increased risk for heart attacks, strokes, kidney failure, certain cancers, diabetes, and premature death. Various studies show that 80 percent of American adults are overweight, and the greatest rate of increase in obesity is occurring in children.

Recent research suggests that one important cause of obesity may be sugared drinks, because calories in liquid form do not suppress appetite as effectively as calories in solid food. Giving toddlers fruit juices and other sugared drinks to quench thirst can form a lifelong habit that sets them up for obesity. Teach your children to drink water or other non-calorie drinks when they are thirsty. The only time it makes sense to consume sugared beverages is during prolonged exercise, where they are a convenient source of energy for muscles that have been depleted of their sugar.

Orthotics may relieve foot pain from running or exercising

People with high arches are at increased risk for foot pain and stress fractures of their bones of their feet because their feet are usually very poor shock absorbers. A report in Cochrane Database of Systematic Reviews (October 2007) shows that custom orthotics can help. When you run rapidly, your foot hits the ground with a force equal to about three times body weight. This force can break bones and damage muscles, nerves, and tendons. So most people land on the outside bottom of their feet and roll inward. This is called pronation which helps absorb some of the shock of the foot striking the ground. However, pronation can cause pain from stretched ligaments (plantar fasciitis), pulled tendons (tendinitis), or pinched nerves (neuromas). Some people are at high risk for injury because they have very stiff ankles that prevent their feet from rolling in normally. These people usually have normally-formed arches and only appear to have high arches.

Orthotics are special custom arch supports that help to absorb shock and prevent foot pain. To see if orthotics are likely to help you, ask your podiatrist to strap your foot with a special taping procedure called a low-dye strap. If this reduces the pain, you probably will benefit from custom orthotics. If orthotics do not cure your problem, pick another sport with limited foot impact such as cycling, swimming or rowing. Other foot problems

Muscle Cramps from Exercise: Causes and Prevention

Exercisers are often told that muscle cramps are caused by lack of salt (sodium) or low potassium. However, recent studies show that athletes in endurance events who suffer cramps usually have normal sodium and potassium levels. A review of the current literature from Buenos Aires, Argentina shows that doctors don't know very much about exercise-induced muscle cramps. The most common cause appears to be muscle damage. Athletes may be able to prevent cramps by slowing down when they feel the muscle pulling and tightening, and picking up the pace only when the muscle feels good again. Journal reference

Cramps may occur as a side effect of drugs used for high cholesterol, high blood pressure or diabetes. Oral contraceptives, various other drugs or alcohol can also cause muscle cramps. If you suffer from recurrent muscle cramps that cannot be explained, check with your doctor. Possible causes include pinched nerves, Parkinson's disease, hypothyroidism, diabetes, narrowed arteries, low blood mineral levels, or metabolic diseases that cause muscle damage. However, most exercisers who experience exercise- associated muscle cramps do not suffer from disease and can usually prevent cramps by slowing down when their muscle start to feel tight. Athletes are usually not willing to do this during competition, so they will continue to suffer from occasional cramps and work them out as they occur. More

Measurable Fat Loss from Exercise

If you weigh yourself before and after an hour or two of exercise, the difference is likely to be fluid loss. However, in events lasting several hours or even several days, measurable fat loss can occur. At a competitive 12-hour indoor stationary bicycle marathon, one athlete took fluids and food throughout the entire competition, and still lost 2.64 pounds. Of this weight loss, 1.98 pounds was due to loss of fat. His calculated muscle weight increased by 1.46 pounds due to damage to the muscle cells, which results in fluid retention in the cells. Journal reference

During vigorous cycling, an athlete can burn between 600 and 1000 calories per hour, so this cyclist probably used more than 9000 calories in his 12-hour event. That is equal to the amount of energy needed to form almost three pounds of fat. He lost only two pounds of fat because of the prodigious amount of food and drink he took in during the marathon. You can lose fat during a single exercise session, but you have to be in extremely good shape and exercise for a very long time to accomplish this. For most exercisers, true weight loss will be measured over weeks or months.

Saunas May Benefit Athletes and Exercisers

For many years I have believed that heating muscles in a hot tub or sauna after exercise interferes with muscle contractions and hampers muscular endurance. However, a study from the University of Otago in New Zealand shows that taking a sauna after workouts for three weeks helped athletes to exercise longer to exhaustion.

Trained runners sat in a humid sauna for 30 minutes at 89.9 degrees centigrade immediately after exercising, 12 times in three weeks. They then ran as hard as they could on a treadmill for about 15 minutes, to exhaustion. Sauna use increased run time to exhaustion by 32 percent, which would equal an improvement of approximately two percent in a full-length endurance time trial. Their blood volumes increased by more than seven percent, and higher blood volume increases endurance. If further research confirms these findings, athletes will be advised to use saunas or hot tubs after their workouts for several weeks before competition. Journal reference

Exercise More Important than Weight Loss for Diabetes Prevention

Exercise is even more important than weight loss for prevention or control of diabetes, according to a report from the Australian National University in Canberra. Dr. Richard Telford concludes that obesity is associated with, but does not cause, diabetes, heart disease and premature death. The health benefits of exercise include increasing cells' ability to respond to insulin, lowering blood sugar levels, and preventing all the side effects of diabetes. Weight loss is not necessary for a person to gain these benefits from an exercise program. Journal references

Most cases of Type II diabetes are caused by the body's inability to respond to insulin. Strengthening muscles makes cells more responsive to insulin. Your ability to respond to insulin depends on the ability of muscles to burn oxygen without producing excessive free radicals (called oxidative capacity). When your body converts food to energy, it produces free radicals that can damage the DNA in your cells to shorten life. Exercise causes cells to burn food for energy more efficiently, without producing large amounts of free radicals.

Thirty-five percent of Americans today can expect to become diabetic. To help prevent diabetes or heart disease, most people should exercise for about an hour a day, alternating vigorous and easy days. If they still have high blood sugar levels, they probably need to exercise more and may also need to take medications. More on treatment of insulin resistance

Caffeine May Prevent Dementia

Caffeine may protect against loss of memory or thinking skills in older women, according to a study published in Neurology. The researchers studied cognitive decline, dementia and caffeine intake of 4,197 women and 2,820 men aged 65 and over in three French cities for four years. They tested the participants' cognitive skills at the start of the study and again at years two and four.

The results showed that compared to women who drank only one cup a day or less, women who drank three or more cups of coffee or tea a day had a 33 per cent reduced risk of decline in verbal retrieval over the four years. The protective effect of caffeine appeared to increase with age, rising from a 27 per cent reduced risk for women aged 65 to 74, to 70 per cent for women aged 80 and over. No link between caffeine and cognitive decline was found in men, nor was caffeine consumption found to affect the incidence of dementia over the four years of the study. Before you increase your coffee intake, note that other studies suggest that caffeine can raise blood sugar and blood pressure. The question of benefits or harm from caffeine is far from settled. Journal reference; more on caffeine

Blood Sugar Levels Affected by Activity

How foods affect blood-sugar levels varies from person to person and from one time to another in a single individual. For example, if you eat a jelly donut in the evening, your blood sugar may rise well over 200 (it should never be higher than 160). If you eat the jelly donut when you have been riding your bike for an hour, your blood sugar level may not rise at all.

Researchers at University Medical Center in Utrecht, the Netherlands showed that eating sugar and flour markedly increases risk for heart attacks in middle-aged women. Being overweight increased the risk even more. More than 15,000 healthy Dutch women, ages 49-70, were followed for nine years. They suffered 556 cases of coronary heart disease and 243 strokes. The ones most likely to be afflicted were overweight women who ate a diet high in foods that cause a high rise in blood sugar. Journal reference

The only places that you can store sugar in your body are your liver and muscles. If you eat lots of sugar or flour when your muscles are full of sugar, sugar goes from your intestines, into your bloodstream and then can spike to high levels. However, during or after prolonged exercise, sugar goes from your intestines into your bloodstream and then directly into your muscles, so it does not spike. For diabetics or overweight people, the safest time to eat foods that cause a high rise in blood sugar is while they are exercising. More on glycemic load of foods; refined carbohydrates; preventing diabetes

Longer Lower Legs Benefit Runners and Walkers

People who have longer lower leg lengths (the distance from knee to ankle) will usually have greater endurance during running or walking than those with shorter lower leg lengths. In a study reported in the Journal of Human Evolution, researchers at the University of Wisconsin showed that people with longer lower legs use less energy when they run.

In a previous paper in the same journal, these authors showed that people with longer lower legs are better able to prevent heat build-up, which slows you down and makes you tired. When you exercise, almost 80 percent of the energy that you use to power your muscles is lost as heat. So the harder you exercise, the more heat you produce and the harder your heart has to work to get rid of the extra heat. You prevent heat buildup by your heart pumping hot blood from your muscles to the skin where it is cooled by sweat and conduction and radiation. Journal references

People with longer lower limbs use up less oxygen and produce less carbon dioxide for the same energy expenditure. Therefore they are more efficient and can go further because their bodies require less oxygen.

You can't change the length of your lower legs, but you can increase running efficiency

Protein: How Much Do You Need?

The Recommended Allowance for protein for most people is about 70 grams per day. Many types of foods contain protein, and it is easy to meet your protein requirements with a typical varied diet. For example, you would meet your daily requirement for protein if you ate two of cups each of beans and whole grains such as barley, brown rice or oatmeal, three ounces of tuna, and two glasses of milk or a vegetarian milk substitute. If you are not sure whether you eat enough protein, keep track by checking the labels of the foods you eat for a few days. You will probably find that you get plenty of protein without any special effort.

Protein is made up of protein building blocks called amino acids. Your stomach acids and enzymes in the stomach and intestines break down proteins into these building blocks, which pass from the intestine into the bloodstream. If your body needs to build protein, your liver combines amino acids to form body proteins. If you don't need all of the protein you have eaten, it is broken down into organic acids and ammonia, which can be used for energy or be converted to fat. If you take in more protein than you need on any given day, it will be stored as fat because you cannot store protein in your body.

Competitive athletes or heavy exercisers need more protein to repair muscles after workouts. Muscles heal from a hard workout when amino acids and other nutrients travel from your bloodstream into the muscles. Eating any foods, particularly those that are good sources of protein, immediately after a workout helps muscles heal faster. More

Restaurant Meals Can Be Healthful

Everyone can enjoy an occasional meal in a restaurant without worrying about the consequences. But if you have to eat in restaurants several times a week, you need to devise ways to make healthful choices and avoid the temptation to over-eat. If you are trying to control weight, diabetes, cholesterol or high blood pressure, you must find ways to meet your special requirements.

First, choose restaurants that gives you a fighting chance. Find a restaurant with a good salad bar and load up on fresh vegetables. Order broiled fish for your entree. Ask to have it prepared with lemon juice instead of butter. Have steamed vegetables as an accompaniment, without added butter, and fresh fruit or fruit ice for dessert.

Asian restaurants often have a wide array of tasty dishes with lots of vegetables. Thai and Vietnamese restaurants and Mongolian grills are good choices if you stick to the vegetarian and seafood entrees. Go easy on the white rice.

Your chances of finding whole grains in a restaurant are slim to none, but if you travel a lot, you might want to pack or shop for your own cereal to eat in your hotel. Large cities and college towns often have vegetarian restaurants that offer varied, flavorful meals made with vegetables, beans and sometimes even whole grains. Whatever you order, watch out for the huge portions that many restaurants serve. Divide it up at the beginning of the meal and save some for the next day's lunch, share with a friend, or just leave it.

List of national chain restaurants that offer good to excellent salad bars and some other healthier choices for people on the go

Walking to Lose Weight: Miles Less Important than Intensity

For exercise to help you control weight, you must exercise fairly intensely or else you need to exercise for many hours, and most people do not have the time to exercise for three or four hours or more every day. A study from the University of Massachusetts in Boston shows that middle-aged women who exercise at very low intensity are fatter and gain weight far more easily than women who exercise more intensely. Journal reference

This is what you would expect. When you exercise intensely enough to raise a sweat, you can increase your metabolism and continue to burn extra calories for several hours after you stop exercising. When you exercise at very low intensity, you do not increase your metabolism and you have to exercise for a very long time to burn a significant number of calories. If walking is your exercise choice for weight loss, walk vigorously enough to sweat and breathe hard.

People who want to use exercise to control weight should first check with their doctors. They should pick an activity that they can do regularly and try to do it every day. On some days, they should try to exercise more intensely, feel sore on the next day, go at low intensity for as many day as it takes for the soreness to go away and then exercise intensely again. People are more likely to stick with an exercise program if they do it with a spouse, a good friend or a personal trainer, or in a social setting such as a class or club. More

Sugar Helps You Exercise Longer

Bicycle racers in long events such as the Tour de France take sugar supplements while they ride to increase their endurance. If you plan to exercise for more than two hours, you can help yourself last longer by taking a source of sugar after 30 minutes and several times more throughout your event.

When you exercise, you convert food to energy for your muscles by stripping off electrons and hydrogen from the foodstuffs. This process manufactures a chemical called ATP that provides energy that does not require oxygen. A study from the University of Waterloo in Ontario, Canada shows that taking sugar during prolonged exercise raises levels of ATP. At exhaustion, ATP levels were at the same low levels in both the group taking sugar and those taking artificial sweeteners. However, prior to exhaustion, those taking sugar had higher levels to help them exercise longer. Journal reference

You do not get this benefit from sugar eaten before you exercise because high blood sugar levels that result will cause your pancreas to release large amounts of insulin. The extra insulin will deplete the sugar stored in your muscles faster and tire you earlier. Thus if you want to exercise intensely for more than a couple of hours, you need to eat or drink a source of carbohydrates at frequent intervals during your activity.

Build Aerobic Capacity by Strengthening Leg Muscles

Aerobic capacity is a measure of your ability to use oxygen to do work. If your body can process more oxygen than that of another person, usually you will be able to run faster, walk or work longer, and have more energy than that person.

The loss of aerobic capacity with aging explains why older people cannot compete effectively against younger ones in endurance events. The good news is that a regular exercise program can help you compensate for this loss by strengthening skeletal muscles and increasing your maximum heart rate.

Tasks that you did without effort when you were younger can become major ordeals that leave you exhausted when you are older. It takes more effort and time to walk up stairs, mow the lawn, fix a faucet or wash the dishes. Dr. Jerome Fleg, a cardiologist at the National Heart, Lung, and Blood Institute, tested 800 men and women over several years and found that their ability to sustain exercise decreased rapidly as they aged. The older they became the faster they lost aerobic capacity.
The men and women lost three to six percent per decade in their 20's and 30's, and 20 percent per decade in their 70's. The men lost aerobic capacity faster than the women. The men lost 8.3 percent of aerobic capacity in their 40's and 23 percent per decade in their 70's. This study was done with people who were healthy enough for vigorous exercise on a treadmill that measured their exercise capacity. People who have had heart attacks, strokes, diabetes or other wasting diseases would lose aerobic capacity much faster than healthy people. Journal reference

A regular exercise program can increase exercise capacity by up to 25 percent, which would give the older participants the same exercise capacity as you would expect in people who are twenty years younger.

With vigorous exercise, you develop stronger skeletal muscles. When you contract your leg muscles, they squeeze against the veins in your legs and pump blood toward your heart. When your leg muscles relax, the veins dilate and fill with blood. This alternate contacting and relaxing pumps extra blood toward your heart. The extra blood returned to the heart stretches and strengthens the heart muscle, causing it to beat faster and with more force. So strengthening your leg muscles increases your maximum heart rate, even as you age.

How Vitamin D Helps to Prevent Cancer

Many recent reports show that vitamin D is far more than just a hormone that strengthens bones. It is necessary for maintaining a healthy immune system. Every day, your body produces millions of cancer cells, and your immunity is supposed to search out and destroy these cells. However, when you lack vitamin D, your immunity is less able to destroy cancer cells. A study from Creighton University in Omaha, Nebraska, showed that women had a 77 percent lower rate of cancer in the second through fourth years of taking calcium and vitamin D pills than women taking placebos. Journal reference

The only really rich food source of vitamin D is fatty fish. Very few people are able to meet their needs for vitamin D from the foods that they eat and have to depend on sunlight to cause their skins to manufacture it. But concern about skin cancer has encouraged many people to avoid direct exposure to sunlight. Vitamin D deficiency is common in northen latitudes, particularly in people who have dark skin that blocks ultraviolet light. It is also common in overweight people because fat cells hold on to vitamin D and prevent it from being utilized. People who are at risk for vitamin D deficiency can ask their doctors to order a blood test to measure vitamin D levels. If low, they may need more sunlight, more fatty fish or vitamin D supplements.

High Resting Heart Rate: Common Causes

If your resting heart rate is greater than 70, check with your doctor to see if your thyroid is overactive, you are anemic, or you have an infection, hidden tumor, a weak heart or other cause of a rapid heart rate. Having a resting heart rate greater than 70 increases your chances of suffering a heart attack. Journal reference

At this time, there is not enough solid data to show that taking drugs to slow heart rate, by itself, will help to prevent heart disease when no cause is found. However, those with chest pain during exercise or blocked blood flow to the heart do benefit from drugs to slow heart rate. Several ongoing studies are trying to determine if all people with heart rates over 80 should take drugs to slow heart rate. Drugs that can be used to slow heart rate and prevent heart attacks include beta blockers, ACE inhibitors, angiotensin receptor blockers, statins or aspirin.

Your "Recovery Heart Rate" is likely to be even more important. Recovery Heart Rate is a measure of fitness and a slow recovery from exercise means that you are out of shape. This test can cause irregular heart beats in people with damaged hearts, so check with your physician before you try it.

To measure recovery heart rate, you exercise on a treadmill (or any other activity) until you are breathing hard, record your heart rate, and hold that pace for at least a minute. Then stop, and measure your pulse rate exactly one minute after stopping. If your heart does not slow down at least thirty beats in the first minute, you are in poor shape and at increased risk for a heart attack. If your heart rate slows down more than fifty beats in the first minute, you are in excellent shape.

You can also use the recovery heart rate to measure your improvement as you get into shape. More

Interval Training to Improve Performance in Sports

The faster an athlete moves in training, the faster he or she will be able to move during competition. So athletes use a training technique called interval training in which they run, cycle, skate, ski or swim very fast for a short time. When they become severely short of breath, they slow down until they recover, and then move very fast again. Researchers at Ithaca College showed that athletes can gain as much by doing this type of intense interval training on consecutive days as on alternate days (Medicine & Science in Sports & Exercise, September 2007).

Interval training causes considerable muscle damage, so it usually leaves athletes sore the next day. Most trainers recommend exercising at a slower pace until the soreness disappears. That is why athletes usually follow each intense day with one or more easy days. However, many competitions require an athlete to exercise flat out for several consecutive days. He may have to compete in multiple preliminary heats over several consecutive days to reach the finals.

In this study, the researchers asked cyclists to perform intense interval on either consecutive days or alternate days. Their improvement in time trials was the same. However, this study did not measure injury rates or risk of overtraining. Most athletes will suffer fewer injuries if they take a hard workout on one day and then go more slowly for as many days as it takes for muscle soreness to go away. More

Bicycling Tips for Blog Action Day

For Blog Action Day, here are some tips for better bicycling. You'll feel virtuous every time you ride your bicycle instead of driving your car!

All cyclists should learn to pedal at a fast cadence, whether you are an experienced racer or a novice recreational rider. Muscle fatigue and damage are caused by excess pressure on the pedals, not by how fast you pedal. Pedaling at a faster cadence with less pressure allows you to pedal longer and harder. However, several researchers have expressed concern that pedaling very fast could decrease blood flow to muscles and thus decrease athletic performance. A study from Kansas State University shows that pedaling fast does not decrease a muscle's flow of blood or ability to extract oxygen from the blood. Once again athletes and coaches find new training and competing methods and years later, scientists tell them that they are correct.

After you have been riding regularly for a time, try to spin your pedals 80 times a minute. In the beginning, you will put so little pressure on your pedals that you will ride very slowly. However, after several weeks of pedaling at a cadence of 80, you will become more comfortable and be able to move fairly well at this pace. As you become stronger, you can maintain this high cadence while using higher gears and pressing on the pedals with more force, so you will be able to ride faster and longer. Journal reference

How to pedal: You should pedal with the ball of your foot, not your arch. The ankle is the fulcrum for the force you generate with your feet. The ball of your foot is further away from the ankle than your arch so you generate far more force with the ball of your foot.

As you straighten your knee, pedal at a 45 degree angle down and forward for the greatest force. Bicycle shoes have cleats that attach to the pedals to keep the ball of your foot over the pedal, where you generate the most force. Don't wear soft-soled shoes that allow the pedals to press against your feet, which can cause pain. Experienced riders know that you should not bend your foot up when you pedal up because it wastes energy and tires you earlier.

My most important tip: get a comfortable bike seat.

Ski Better By Preparing Now

If you love to ski, it's time to think about getting ready. The best way to train for skiing is to ski, but snow isn't always available. To prepare for a ski trip, you need to strengthen both your heart muscles and your skeletal muscles. You can strengthen your heart for skiing with any exercise that will raise your heart rate for at least 10 minutes, three times a week. However, to prepare your muscles for skiing, you have to use activities that use your upper legs, such as skating or riding a bicycle. The average bicycle rider is far better prepared for skiing than the average runner. Many joggers who can easily run ten miles find that they can't ski very long because their upper leg muscles tire and hurt after just a few minutes of skiing.

You drive yourself forward in skiing with the muscles in your upper legs. Running stresses primarily the muscles in your lower legs. It does not strengthen the muscles in the upper legs enough to allow the average person to ski for any length of time. Running stresses your upper leg muscles only when you use them to lift you up when you run hard up hills. Since you ski by bouncing up and down on your knees and shushing forward from your hips, the best sports to prepare for skiing are those that stress primarily your thigh and upper leg muscles. You can use the popular indoor exercise machines that mimic cross-country skiing motions, or ski on dry roads with roller-skis. In-line skating or cycling are good choices for outdoor preparation, particularly if you climb lots of hills. Add a weight training program to strengthen your upper body and arms as well as your legs, and you’ll be ready for the snow.

Sorbitol: Poison in Your Body, OK in Foods

When blood sugar levels rise too high, sugar sticks to the surface membranes of cells. The sugar, glucose, is converted into another sugar, fructose, and eventually to sorbitol, which destroys the cells. This cell damage leads to heart attacks, strokes, blindness, deafness, kidney damage and the other harmful effects of diabetes.

The same chemical is harmless when it is used in foods because you do not absorb it. Sugar alcohols such as sorbitol, mannitol or xylitol have almost the same chemical structures as carbohydrates, but they have an alcohol end on one side. This prevents them from being absorbed from your intestines, so they can be used to sweeten food without contributing any calories. The sugar alcohols pass undigested to your colon where they are fermented by bacteria, so large amounts can cause gas and diarrhea. That's why sorbitol is used only in foods such as hard candy or gum, where portion sizes are very small. How to keep blood sugar levels from rising too high; how to recognize pre-diabetes

Muscles Can Be Strengthened at Any Age

You are never too old to enlarge and strengthen your muscles. A study from Copenhagen, Denmark shows that just 12 weeks of lifting weights significantly strengthened the muscles of men 85 to 97 years of age (Scandinavian Journal of Medicine & Science in Sports, August 2007). After 12 weeks of training, the cross sectional circumference of their quad muscles in the front of their upper legs increased by 10 percent, and muscle strength increased by 35 to 50 percent. Furthermore, the muscle fibers that are used for strength and speed increased significantly.

Frailty in old age is caused by lack of exercise, not just by growing old. With aging, you lose nerves. Each nerve is attached to a single muscle fiber, so as you lose muscle fibers you become weaker. Older people who exercise against resistance can enlarge their muscle fibers. This counteracts the effects of losing fibers and they can retain a significant amount of strength.

People with weak hearts can suffer heart damage with vigorous exercise. Before an older person starts an exercise program, it may be wise to check with a doctor to make sure that the heart is sound. The most dependable heart test is a thallium stress test. Then engage a personal trainer to teach the person how to exercise on a series of individual weight lifting machines that stress different muscle groups. Usually the recommended program involves going to each machine and lifting and lowering the weight on that machine in a single set of three to ten repetitions. Most people can do this three or more times a week. Fitness newsletter

Caffeine, Exercise Help to Prevent Skin Cancer

High doses of ultraviolet light damage the DNA in skin cells. Normally, damaged cells commit suicide by a process called apoptosis, so that they do not become cancerous. However, damaged cells that do not undergo apoptosis live to become cancerous. A report from Rutgers University showed that exercise and caffeine help to prevent skin cancer. Researchers divided mice into four groups: 1) inactivity, 2) exercise, 3) caffeine and 4) exercise and caffeine. Then all of the mice were exposed to high doses of ultraviolet B light that damaged their skin cells. Caffeine caused a 95 percent increase in apoptosis, exercise caused a 120 percent increase, and those who both exercised and took caffeine had a 400 percent increase in apoptosis.

Cells in your body have multiple small areas called mitochondria that turn food into energy by knocking hydrogen and electrons from carbohydrates, fats, and proteins. The freed electrons can attach to oxygen to form reactive oxygen species (free radicals) that stick to the DNA of cells to damage them and cause cancer. Exercise teaches your mitochondria to turn food into energy with far fewer free electrons, so there are fewer free radicals to damage cells. Caffeine markedly increases an animal's ability to exercise for longer periods of time. Journal reference

Tapering for Athletes and Ordinary Exercisers

Tapering refers to the period just before a major race or game, when an athlete reduces workload to be in peak shape on the day of the competition. Ordinary exercisers can apply this training principle when they plan to enter a local race or charity event.

Top athletes must spend a tremendous amount of time training to be able to compete successfully. Their huge volume of work leaves them near exhaustion and before major competitions, they have to find the best way to reduce fatigue while retaining fitness. Many studies have been done to help athletes and coaches decide on the best strategy. Researchers at the University of Montreal compiled the results of 27 scientifically acceptable studies. They concluded that the best duration of tapering is two weeks, the optimum training volume reduction is by 40 to 60 percent, and the intensity of workouts should be maintained (Medicine & Science in Sports & Exercise, August 2007).

Training load during taper: Almost all of the studies agree that athletes should reduce the amount of work they do. While each athlete must decide on his optimal reduction, many bicycle racers drop from up to 400 miles a week down to fewer than 200, and many runners drop from above 100 miles to fewer than 40.

Duration of taper: A tapering period of eight to fourteen days appears to optimize performance in which an athlete can lose his fatigue and still maintain his ability to compete at high intensity.

Intensity during taper: Almost all studies show that athletes need to maintain intensity during tapering. During background training, they take workouts in which they run, skate, ski, cycle and swim very fast two or three times a week. They often continue these intense workouts during the two-week taper, stopping a few days before the competition.

While nobody really knows how tapering improves performance, most researchers believe that it increases a person's maximal ability to take in and use oxygen (VO2max). This is explained by increases of blood volume, red cell production and enzymes that utilize oxygen in the production of energy. Since fatigue interferes with coordination, tapering alleviates fatigue to improve efficiency of movement that, in turn, improves a person's ability to use oxygen for energy. More training tips

Obesity Contributes to Vitamin D Deficiency

Lack of vitamin D can cause osteoporosis, diabetes, heart disease, degenerative arthritis, infertility, autoimmune diseases, and cancers of the breast, prostate, colon or skin. Sunlight is the best way to meet your needs for vitamin D, but dermatologists have been telling us for years that sunlight can cause skin cancer. Increased use of sunscreens use may have had the unwanted side effect of widespread vitamin D deficiency. The rise in obesity may also be contributing to increased rates of vitamin D deficiency. Once vitamin D gets into fat cells, the fat cells hold on to that vitamin so tightly that it is not easily released into the rest of the body to do its job. Furthermore, vitamin D lowers blood levels of leptin, a hormone released by fat cells to tell your brain that you are full and to stop eating. So obesity can make you deficient in vitamin D, and lack of vitamin D can make you even fatter.

Very few people are able to meet their needs for vitamin D from food. People who tan easily and are not sensitive to sunlight should probably use sunscreen only on their faces and arms, allowing their legs and backs to be exposed to the sun. However, many people, particularly those with dark skin and those who live in northern latitudes, may need to take vitamin D supplements. Check with your doctor. More

Rest Periods Probably Do Not Increase Weight Loss

Researchers at the University of Tokyo claim that they have shown that intermittent exercise will help you to lose more weight than continuous exercise at the same intensity. Seven men participated in three different trials: 1) one hour at an intensity equal to 60 percent of maximum oxygen uptake; 2) 30 minutes at the same intensity followed by a 20-minute rest, followed by 30 more minutes of exercise at the same intensity; and 3) one hour of rest. The trial with two bouts of 30 minutes separated by a 20-minute rest burned the most fat. This intermittent exercise trial resulted in higher blood free fatty acid, glycerol and epinephrine levels, and significantly lower values of insulin and glucose.

If these researchers are correct, scientists may need to revamp their ideas about the best exercise regimen for weight loss, recommending multiple bouts of exercise with intermittent rest periods. However, there may be another way to explain the results of this study. Fat cells release fat during exercise and then reabsorb some of that fat during rest. During the intermittent exercise trial, fat cells would release fat in the first bout of exercise, some of the released fat would return during the rest period, and then during the second bout of exercise, the fat cells would appear to have released more fat because they released new fat and some of the more-soluble fat that had returned to the fat cells. The increase in fat loss would be due to the fat that had re-entered the cells during the rest period, and would not make any difference in total weight loss.

Unless the researchers can show that intermittent exercise burns more total fat than continuous exercise, there is no need to change your exercise routine. Weight loss is determined by how hard and how long you exercise, not by the timing of your rest periods. Journal reference; more on exercise for weight loss

Prevent Weight Gain with Exercise: How Much is Enough?

Most people could eat all they want and not gain weight, but they would have to do a lot of exercising to accomplish this. A study from Zurich shows that it takes at least five hours per week of vigorous exercise to avoid gaining weight with aging (Revue Suisse de M├ędecine Praxis, May 2007). They showed that the average Swiss recreational cyclist, aged 55 to 77, has gained almost two pounds per decade from youth, compared to the non-exercising males in the same age group who gained four pounds per decade. The rate of overweight among these year-round cyclists increased from 7.4 percent in their youthful days to 25 percent by the time they reached their fifties.

If you are in an exercise program and are still gaining weight, you need to exercise more. For many people with jobs, this can be a problem. You may have to go to exercise classes in the evenings after work. Heavy morning exercise can leave you too exhausted to get through the day. You will be more likely to spend many weekend hours exercising if you have an activity that is sociable and fun. Try joining the local bicycle club or road runners club and go out for extended workouts with other members.

High Fructose Corn Syrup May Be Harmful: New Evidence

The food industry continues to insist that there is no difference between high fructose corn syrup (HCFS) and table sugar, but researchers at Rutgers University have a different opinion. They have found new evidence that soft drinks sweetened with (HFCS) cause tissue damage and may contribute to the development of diabetes, particularly in children. Chi-Tang Ho, Ph.D., and his colleagues conducted tests of eleven carbonated beverages containing HFCS. He found "astonishingly high levels of reactive carbonyls" in those beverages. These highly-reactive compounds associated with "unbound" fructose and glucose molecules are believed to cause tissue damage. Reactive carbonyls are not present in table sugar, whose fructose and glucose components are "bound" and chemically stable. The researchers state that reactive carbonyls are elevated in the blood of individuals with diabetes and are linked to the complications of the disease.

This study was reported at the 234th national meeting of the American Chemical Society. While we await further research, I will continue to recommend avoiding beverages sweetened with HFCS or any other sugars except during vigorous, prolonged exercise. More on high fructose corn syrup

Arch Height Should Guide Choice of Shoes for Running or Exercise Walking

Check the height of your arches when you shop for new running or walking shoes. If you have high arches, you usually need shoes with good shock absorption. If you have low arches, you will probably benefit from shoes with good motion control (Gait & Posture, July 2007).

When you run, you land on the outside bottom of your foot and roll inward. This is called pronation, which helps to protect you from injury. If you landed on your foot and did not roll, the force of the impact would be transmitted up your leg to increase your chance of breaking bones and tearing muscles. However, as you roll in from the outside bottom to the inside bottom of your foot, you will see that your lower leg twists inward. Excessive pronation twists your lower leg, which can cause stress fractures of the lower leg bones. It can cause knee pain because it forces your kneecap to rub against the bone of your upper leg. Excessive pronation can even twist your hip joint to cause pain in the hips and lower back.

People with low arches are most likely to roll in too much. Their arches may be normal but appear to be low because the ankles allow the arch to go down so far that it touches the ground. These are the people who need shoes with "motion control" to limit how far their legs twist inward. Motion control features include extra padding in the area where the arch fits in the shoe; a stiffer collar that extends from the laces to the sole to limit rolling in; and a firm stiff piece in the back of the shoe, called a counter, that grips the back of the heel to limit motion.

People with high arches hit the ground with great impact. They need running shoes that limit the force of the foot when it hits the ground. Runners with high arches should seek shoes that have soles and heels with special properties to absorb road shock. More

Air Pollution Should Not Keep You From Exercising

It's healthful to exercise and harmful to breathe polluted air, so how can you decide whether you are doing more harm than good? The worst time for pollution is when clouds cover the sky and automobiles fill the roads. Automobile exhaust fumes are the principal source of air pollution in most cities, and overlying clouds increase pollution. Usually the sun's rays heat the ground to warm air closest to the ground. Hot air rises, taking large amounts of pollutants skyward. On air inversion days, the clouds prevent the sun's rays from getting through to the ground, so the air near the ground is not heated, remains colder and doesn't rise, causing the air with its pollutants to remain close to the ground.

Air pollutants such as carbon monoxide, ozone, carbon dioxide, and sulfur dioxide can damage your lungs. When you exercise, you breathe more deeply and more frequently so that you breathe in more pollutants. However, you don't retain more pollution. Bicycle riders in rush hour downtown Washington traffic breathe in more carbon monoxide than car riders do, but have lower blood levels of carbon monoxide. So keep exercising, but if possible, try to avoid heavily trafficked streets, and exercise before the heavy morning traffic peak or at least two hours after the evening rush hour ends.
Should you try to breathe only through your nose?

Portion Sizes Do Matter

Whether or not you are overweight, portion sizes of food are a major factor in determining how much you eat. In a recent study, researchers at Pennsylvania State University in University Park measured how much normal and overweight people ate (Obesity, June 2007). They then fed these people fifty percent larger portions of food at every meal. Both overweight and normal weight people increased their intake of food equally and they continued to eat far more food for the duration of the study.

You might expect that when people overeat, they would eventually reach a point where they feel full and stop taking in too much food. However, this has not been shown to be the case. When people are offered large portion sizes, they continue to eat more food and it doesn't matter whether they were fat or thin when they received the larger portions. More

Repetition Makes Muscles More Efficient

Training is specific, so the more you practice your sport, the better you are able to do it. That's why triathletes who compete and train in three sports are relatively mediocre in each sport when compared to those who only run, cycle or swim. (Sports Biomechanics, Volume 6, Issue 1, 2007). In this study, elite cyclists produced significantly more effective force on their pedals than triathletes. They had far less wasted side-to-side motion, and they required less oxygen to do the same amount of work.

Repeating the same motion over and over causes your muscles to become more efficient so they can generate more power with less oxygen. For example, when you run, you use your arms to maintain your center of gravity. When your right leg moves forward, so does your left arm; your left leg and right arm move backward. Efficiency requires that you move your body forward with the least motion wasted going side to side, so that the more energy you use to drive your body forward, the less oxygen your muscles require. The same efficiency is required in pedaling a bicycle. You are supposed to move your pedals through a full 360 degrees, rather than just pushing through one phase of pedaling, and you move your body from side to side as little as possible.

In competitive sports today, the best athletes put in the most time training. Runners usually run more than 100 miles a week, cyclists often go over 400 miles a week, and weight lifters spend many hours each day in the gym lifting prodigious amounts of weights. If you want to compete at a high level, you need to spend a lot of time practicing. More on training and fitness

Muscles Cannot Become Fat

Some people believe that if they build muscles and then stop exercising, the muscles will turn into fat. This is not a reason to avoid exercise, because muscles can't possibly turn to fat. When you exercise, your muscles become larger and stronger because exercise causes extra protein building blocks, called amino acids, to deposit in muscles. All day long, amino acids pass from your muscles into your bloodstream and then back into muscles. Exercise is the major stimulus to force amino acids back into muscles.

When you stop exercising, fewer amino acids go into your muscles so the muscles get smaller. Your body has no way to store extra protein, so amino acids that are not used in your muscles are picked up by your liver, which uses them for energy or converts them into fat for storage. So if you stop exercising, you have to eat less or you will gain weight. But muscles never turn into fat. More on muscles and protein

Reduce Oxidants Instead of Taking Antioxidants

Instead of taking antioxidants, researchers now think you should aim to prevent your mitochondria from making excessive amounts of oxidants. The cells of your body have tiny chambers in them called mitochondria that help convert food to energy. When they do this, they knock of electrons from nutrients, and these extra electrons eventually end up attached to oxygen. Electron-charged oxygen, called reactive oxygen species or free radicals, then attach to the DNA cells to damage them and shorten your life.

At this time, scientists have found only one practical way to reduce the amount of oxidants produced by mitochondria: exercise. Vigorous exercise helps the mitochondria burn food more cleanly with the production of fewer oxidants. The same effect can be accomplished with severe calorie restriction, or with chemicals such as resveratrol or dichloroacetate, but the results of these studies in animals have not yet been successfully applied to humans.

Here's another study showing that taking antioxidant vitamins does not prevent heart attacks (Archives of Internal Medicine, August 2007). 8,171 women over the age of 40, all with a history of heart disease or with three or more risk factors for that disease (high blood pressure, diabetes or high cholesterol) were randomly assigned into groups and given either 500 milligrams of ascorbic acid (vitamin C) every day, 600 units of vitamin E every other day or 50 milligrams of beta carotene every other day. None of the antioxidant vitamins, either alone or in combination, helped reduce the risk of a heart attack. As of today, there is no evidence that taking antioxidants vitamin pills helps prevent heart attacks. More on cell mitochondria

Partial Knee Replacement: Less Pain, but Not for Everyone

The ends of bones are soft, so they must be covered with a thick white gristle called cartilage. Many people suffer from knee pain because the cartilage is damaged. They may have osteoarthritis in which the cartilage wears away, or they may have damaged cartilage in an accident or by playing sports. Once damaged, cartilage can never heal; the person spends the rest of his life losing cartilage until the cartilage is completely gone and the knee hurts 24 hours a day.

Until recently, the only effective treatment has been to cut out the ends of the bones of the knee and replace the entire knee joint. Now for some people, a simpler procedure may be effective: partial knee replacement, called unicompartmental knee arthroplasty. The surgeon removes just part of the cartilages and bones on the upper and lower legs on one side of the knee.

However, this procedure is not for everyone. Since partial replacements are more fragile than total knee replacements and do not last as long, the patient should be over 60, not obese and not a vigorous exerciser. All of the knee ligaments should be intact, the other compartments of the knee should not be damaged, and there should be no disease, such as rheumatoid arthritis, that causes progressive joint damage. If a partial knee replacement fails, more extensive surgery will be required for a total knee replacement. If you think you may be a candidate for partial knee replacement, check with an orthopedist with experience in this procedure.

After any surgery on knee cartilage, you must protect that knee for the rest of your life. Running and jumping cause further damage, while pedaling and swimming usually do not. More on total knee replacement; more on arthroscopic knee surgery

Awkward Running Form Can Be Improved

Many people look terribly uncoordinated when they run. Telling them to change their form will just make them more uncoordinated. If a coach criticizes a team member for poor running form and doesn't correct the underlying causes, the person is likely to become self-conscious about how he or she looks, and run even more slowly. Coordination usually improves just with repeated practice in the chosen sport.

Running form can improve markedly if you can correct muscle imbalances and structural abnormalities with appropriate exercises and perhaps mechanical devices. A coach can videotape the athletes while they run, then review the tape in slow motion to analyze the mechanical defects. For example, leaning forward during running is often caused by weak back muscles, which can be treated with exercises to strengthen the back. Pointing the toes out is often caused by weak lower leg muscles and can be corrected by doing exercises to strengthen the shin muscles. Leaning back on the heels after foot plant can be caused by excessive rolling-in motion of the feet or weak calf muscles.

Treatment often includes special inserts in the shoes and calf strengthening exercises, such as toe raises while holding a heavy weight in the hands. Holding the shoulders up towards the ears during running is usually caused by weak shoulder muscles, which can be corrected by shrugging the shoulders while holding weights. A low knee-lift is often caused by weak quadriceps muscles in the front of the upper leg. The quadriceps can be strengthened by pedaling a bicycle, skating, or running up hills. How to run faster

Finger length may indicate athletic ability

High levels of the male hormone, testosterone, cause the fourth finger of unborn children to grow more than the second. This explains why men usually have proportionately longer fourth fingers than women do. Scientists can use the length of the fourth finger to tell which women were exposed to higher levels of testosterone before they were born. Researchers at the University of Central Lancashire in Preston, England showed that women whose fourth finger is much longer than their second were faster cross country runners in races of one to four miles (American Journal of Human Biology, May-June 2007).

The finger length was measured from the bottom crease where the finger joins the hand to the tip of the finger. Men are typically bigger and stronger than women, and have larger muscles and bones, because of their higher testosterone levels. Testosterone helps people to recover faster from hard workouts, so they can do more work and become better athletes. Women exposed to higher levels of testosterone in utero have higher ratios of their fourth to second fingers and often are better athletes.

Most common cause of muscle cramps: lack of salt

The most common cause of muscle cramps in exercisers is lack of salt, according to a report from the University of Oklahoma. The authors cite studies of tennis and football players showing that crampers tend to be salty sweaters, and of triathletes who cramp losing more salt during a race than peers who did not cramp. They found that intravenous saline can reverse cramping, and that more salt in the diet or in sports drinks can help to prevent heat cramping.

Until now, the leading theory was that most cases of muscle cramps in competitive athletes are caused by an exaggerated "stretch reflex". When you stretch a muscle, it pulls on its tendon. Stretch reflex nerves in that tendon send a message back to the spinal cord (not the brain), and then the "stretch reflex" in the spinal cord sends a message along nerves from the spine to cause the muscle to contract. During fatigue, the muscle retains its contraction to form a cramp. A study from South Africa showed that the most likely cause is muscle fatigue or tearing of the muscle itself. If this is true, muscle cramps during endurance events can be prevented by slowing down when you feel excessive soreness in one muscle group or straining in a muscle. Of course, competitive athletes will not do this, and they pay for it with muscle cramps.

For many years I have recommended eating salted peanuts or other salty foods during heavy exercise, but other doctors believe that extra salt will raise blood pressure. If this is a concern for you, get a wrist cuff monitor and check your blood pressure every day. You are likely to find that your blood pressure goes down, not up, with regular exercise even when you add salt. Journal reference; salt and blood pressure

Acne patients improve on low-glycemic-index diet

Most dermatologists tell their patients that diet has nothing to do with acne, but researchers at RMIT University in Melbourne, Australia presented a paper showing that an experimental low glycemic–load diet helps to improve acne. After 12 weeks, those on the special diet had lower acne lesion counts, lower body weight and lower blood levels of male hormones, compared to those who were not on the special diet.

Acne is a skin disease in which a person's skin glands produce excessive amounts of oil that is converted from a colorless liquid to a more solid white sebum. Then the body causes an immune reaction that causes redness and swelling around the oil glands on the surface of the skin. High levels of male hormones increase oil secretion, while female hormones usually lower it. This study shows that foods that cause a high rise in blood sugar may increase male hormones, oil production and acne.
Journal reference; explanation of low-glycemic-index diet

Fish Oil Supplements Can Raise LDL Cholesterol

Nobody really knows whether fish oil supplements prevent heart attacts as effectively as eating fish. However, both eating fish and taking fish oil pills can lower triglycerides and prevent clotting, which may help prevent heart attacks. Heart attacks occur when a plaque breaks off from the wall of arteries leading to the heart and travels down the ever-narrowing artery until it stops and forms a clot that blocks blood flow to the heart.

A recent report shows that nine grams of fish oil supplements per day may not be completely safe because they can cause a substantial rise in the bad LDL cholesterol (from 106 to 186) that increases heart attack risk (The Annals of Pharmacotherapy, July 2007). Fish oil supplements lower triglycerides by reducing liver cells' ability to manufacture triglycerides. At the same time, they can block the LDL receptors on liver cells from removing LDL from the bloodstream. Once again, I recommend getting the nutrients your body needs from food rather than from supplements. Diet to lower cholesterol; how to raise the good HDL cholesterol

Injuries more likely if you have only one sport

Triathletes are injured only about one third as often as marathon runners even though they do far more work in their program of swimming, cycling and running. Training intelligently for three sports is less likely to injure you than training very hard for one. Training is limited by damage to skeletal muscles. Every time you exercise, your muscles develop small tears with bleeding. It takes at least 48 hours for muscles to heal from exercise. Each sport stresses a particular group of muscles most. Marathon runners who train every day stress the same muscles and do not allow adequate time to recover from the previous day's workout, so they are at increased risk for injury.

Top triathletes train in different sports on consecutive days. Running stresses the lower leg muscles most, cycling stresses the upper leg muscles most and swimming stresses the arms and shoulders most. Triathletes usually set up a workout schedule that includes two sports on one day and one on the next. Of the three sports, running causes the most muscle damage. Muscles are protected by the water in swimming and by the rotary pedal motion in cycling. However, the force of the footstrike in running tears up muscles. So a knowledgeable triathlete runs on one day and cycles and swims on the next. This way each stressed muscle group has a 48-hour recovery before the next workout. You can apply these same rules for alternating any two or three different activities. Principles of training

Does High Fructose Corn Syrup Cause Obesity?

For the last 25 years, soft drinks have used high fructose corn syrup as their major form of sweetening. This coincides with a major increase in obesity in America. However, a study from the University of Washington shows that there is no evidence that commercial beverages sweetened with either sucrose or high fructose corn syrup have significantly different effects on hunger or how much you eat (American Journal of Clinical Nutrition, July 2007).

In another study from Purdue University, subjects were given three different food groups in both liquid and solid forms (International Journal of Obesity, June 2007). No matter what they ate, the subjects ate far more calories on the days that they took in foods in liquid form. This shows that liquid forms of food are interpreted in the brain as less filling, and therefore people take in more calories when their beverages contain calories. Interestingly, the increase in calories associated with liquid forms of foods was nearly the same in obese and skinny people.

A single 12-ounce can of soda contains 13 teaspoons of high fructose corn syrup and the average American consumes almost 60 pounds of it, according to the U.S. Department of Agriculture. The leading theory now is that any sugar in liquid form does not make you feel full the way solid food does. Therefore if weight is a problem for you, you should not take in calories in liquid form. Drink water or other zero-calorie beverages instead. More

Spot Reduction Exercises Don't Work

Many people believe that if they do enough sit-ups they will get rid of belly fat, but your body does not work that way. Exercising a specific muscle does not get rid of more fat over that muscle in comparison to the rest of your body. If it did, tennis players would have less fat in their tennis arms, and this does not happen. Strength training strengthens weak muscles, but it cannot remove fat specifically over the strengthened muscle.

A recent study from the University of Connecticut showed that men who exercised one arm against heavy resistance for 12 weeks appeared to lose more fat in their exercised arm than their inactive one when fat was measured by a caliper that calculated skin thickness (Medicine & Science in Sports & Exercise, July 2007). However, when the same authors used an MRI machine to measure fat underneath the skin, there was no difference between the exercised and non- exercised arms.

When you take in more calories than your body burns, you store the extra calories as fat. More than half of the fat in your body is stored underneath your skin and over your muscles. Your stomach will look better when your belly muscles are strong, but sit-ups or crunches will not remove extra fat from your belly. The only way to lose fat from a specific part of your body is to lose weight overall. More on belly fat

Selenium May Increase Diabetes Risk

If you take selenium pills, you may be increasing your chances of developing diabetes, according to a report from the Nutritional Prevention of Cancer (NPC) trial (Annals of Internal Medicine, August 2007). This study is the largest and longest available experimental study of selenium supplements and was done by randomly selecting people for either placebos or selenium and then checking to see who develops diabetes.

In 1973, researchers showed that selenium protects against oxidative damage, chemical reactions that damage cells and shorten life. However, there is a narrow margin between getting enough selenium to keep you healthy and taking too much. High levels of selenium bind to and damage many essential body proteins. In the United States, dietary levels of selenium are high so there is little chances of developing selenium deficiency. Furthermore, selenium can be toxic to humans at low doses. Symptoms of poisoning include loss of hair and nails, tiredness, nerve or liver damage, and as shown in this study, diabetes. Selenium over-dosage cause oxidants to be formed in the body. They block the body's ability to respond to insulin and can even damage the insulin-producing cells in the pancreas. We do not know definitely that selenium causes diabetes, but until more data is available, most authorities recommend that people not take selenium supplements unless they have been tested and shown to have a selenium deficiency. Assess your risk for diabetes; weekly newsletter

Low Carb Diet Does Not Increase Endurance or Speed

Some athletes and exercisers believe that a low carbohydrate diet will increase their endurance and speed, but there is no evidence that it will. Runners get fuel for their muscles from fat and sugar in muscles, fat and sugar in the bloodstream and, to a lesser degree, from protein. The key to increasing endurance for racing is to store as much sugar in muscles before you race and keep it there as long as possible. Muscle sugar gives you the most energy for the least amount of oxygen.

Restricting carbohydrates does not stimulate muscles to store more sugar (Sports Medicine, April-May 2007). A low carbohydrate diet may impair performance if carried out for extended periods because a runner cannot train on a low- carbohydrate diet. If there are benefits from depleting muscles of their stored sugar supply, they probably come from the high- volume depletion workouts, not from the diet. To maximize stored muscle sugar, a runner should reduce his workouts for two to three days before a race. He or she should not restrict carbohydrates.

Another study from The University of Bern in Switzerland showed that a high carbohydrate, high-fat diet for three days before competition can help athletes store more fat in their muscles and use much more muscle fat for energy during exercise. Endurance-trained athletes exercised for three hours to empty sugar and fat reserves from their muscles. Then they ate a high-carbohydrate, low-fat diet for 2.5 days or the same diet with lots of added fat for the last 1.5 days. Athletes who ate the high-carbohydrate, high-fat diet stored 55 percent more fat in their muscles and used more than three times as much of that fat during exercise. More

Athletes, exercisers and spectators: heed lightning warnings

People who are killed by lightning are often spectators or participants in sporting events. In the United States each year, lightning kills more than 70 people and injures more than 300 people, often permanently. Lightning strikes without warning, so sponsors of outdoor athletic events should have loudspeakers, sirens or horns to alert people to approaching electrical storms.

Water, metal and high objects attract lightning. When an electrical storm starts, try to enter a building or your automobile as quickly as possible. Get in your car, not near it. Standing near a car increases your risk of being struck by lightening because you are standing near metal. To avoid being near metal, get off your bike and away from it when you seek shelter. If you are on the golf course, get away from your golf clubs and carts and anything that contains metal.

If you are in an open field, you are the tallest object and therefore most likely to attract lightening. Standing makes you the tallest object, so if you cannot get to a sheltering building, go to a low spot and crouch down. Avoid being near the tallest object; do not stand under a single tree or by a pole. Standing under a tree that is shorter than other trees in the area is better. It is safer to be in a forest with many trees than to be under a single tree.

Don't stay in or near water. Just being near a lake, ocean or swimming pool increases your chances of being struck by lightning. Water sports such as swimming, fishing and boating increase your risk. Take the lifeguard's warnings or radio bulletins seriously, get out of the water and go to the nearest shelter. Fitness news

Napping Makes You Smarter

Two studies from Harvard show that napping make you smarter. I learned this for the first time when I was in the 7th grade. I would be in school from 8 AM to 3PM, go to work in the afternoon, and then come home at 6PM, eat supper and try to study and learn nothing. I would spend more time lying in bed thinking about studying than actually studying. So, in the seventh grade at age 12, I started a lifetime habit of sleeping every afternoon, even if I think that I don't need to sleep. I find that after just 30 to 60 minutes of sleep, I can think more clearly and do more work. If I don't sleep, I cannot write or think clearly.

Matthew Walker's study supports what I learned almost 60 year ago. He taught people to type a long list of words on a computer. He showed that those who were trained at night and were tested after a long night's sleep did far better than those who were trained in the morning and tested 12 hours later without sleeping. Thus, those who were tested after a night's sleep did much better than those who were tested after 12 hours being awake.

In the second study, Sara Mednick reported that she compared a person's ability to learn after no sleep, a 30-minute nap, or a 60 minute nap. Those who had a 30-minute nap did better than those who didn't nap, while those who took a 60-minute nap did far better than those who took only a 30-minute nap. When you start a nap, your eyes are kept still, called non-rapid-eye-movement sleep. You drop down from stage one sleep into a deeper stage two, then a deeper stage three, and then your eyes start to move rapidly back and forth. This is called Rapid Eye Movement sleep, also know as REM sleep. You learn best if you wake up right after non-rapid-eye-movement sleep (stage 2). And you get more non rapid eye movement sleep (stage 2) in a 60-minute nap than a 30-minute nap.

If you feel tired most afternoons, you are normal. In many parts of the world it is traditional to take an afternoon nap or siesta. Studies of office workers and school children show that people work best in the early morning. As the morning progresses, they lose their ability to concentrate, go out to lunch and function way below their capacity for the rest of the day. A study from the University of Pennsylvania Hospital shows that pilots, who sleep just 20 minutes during flights while their copilots take over, are more alert, attentive and responsive than those who don't nap.

It gets worse as you age. Older people fall asleep while you talk to them in the afternoon. An article in the medical journal, SLEEP, shows that a regular afternoon nap can help older people remain awake afternoon and evenings. They took a planned nap for 90 minutes between 1:30 and 3:00 in the afternoon. They were hooked up to special machines that showed that most slept for about one of the one and a half hours they lay in bed. These people had a remarkable improvement in their alertness in the afternoon and evening. They did not sleep as deeply at night and did awake a little earlier in the morning, but felt that the gain in alertness afternoons and evenings was far more important than this slight loss of sleep at night. Their sleep cycles however remained unchanged, so they still went to bed at their usual times.

Tiredness is a signal that your brain needs a rest. If you suffer from afternoon tiredness, find a quiet place to lie down during your lunch hour and take a nap. There is no data to support exercising when you feel tired because exercise does not perk you up. Recommendations to eat protein-rich foods and avoid carbohydrate ones are not based on solid data. Eating does not prevent afternoon tiredness and the drop in mental and physical performance. The only effective treatment for tiredness is rest. Set a radio to wake you to music, rather than a harsh sound that will jolt you, and expect to be far more productive than you were when you struggled to get through the afternoon and evenings without napping. Journal references; free fitness and health newsletter

Fasting Triglycerides Test for Heart Attack Risk Unreliable

For more than 50 years doctors have used fasting blood triglyceride levels to predict a future heart attack, but now two studies in the Journal of the American Medical Association show that non-fasting blood triglyceride levels are far more dependable (July 18, 2007). When your blood sugar rises too high after eating, your pancreas releases huge amounts of insulin. Insulin converts sugar to triglycerides. Triglycerides are therefore a marker for a high blood sugar levels that damage arteries to cause heart attacks. More than 75 percent of diabetics die of heart disease.

Many people have normal blood sugar and triglyceride levels after an overnight fast, but have their blood sugar levels rise too high after eating and therefore have a high rise in triglycerides only after eating. This means that having normal triglycerides after fasting does not rule out high risk for a heart attack. High triglycerides after eating shows that you have high blood sugar levels and should restrict foods and beverages made with sugar, flour or other refined carbohydrates, the foods that cause the highest rise in blood sugar.

You can tell if you are at high risk for diabetes if you store fat primarily in your belly. Pinch your belly; if you can pinch an inch, you are at increased risk and should get a blood test called HBA1C. Having high blood levels of triglycerides and low levels of the good HDL cholesterol that helps prevent heart attacks also increases your risk for diabetes. When you eat sugar or flour, your blood sugar rises too high. This causes your pancreas to release insulin that converts sugar to triglycerides, which are poured into your bloodstream. Then the good HDL cholesterol tries to remove triglycerides by carrying them back into the liver, so having high blood levels of triglycerides and low blood levels of the good HDL cholesterol are both individual risk factors for diabetes. More on pre-diabetes; more on insulin resistance

Muscle Sugar More Important Than Fluid for Endurance

How fast you can move and how long you can exercise intensely depends on the amount of sugar (glycogen) stored in your muscles. The same rule applies in all sports: when muscles run out of their stored sugar supply, they require more oxygen and you have to slow down.

Fluid is less important than muscle sugar because dehydration will not cause you to slow down until your blood volume is reduced. As you lose fluid from sweating, interstitial fluid stored around cells is released into the blood to maintain blood volume. When you compete is sports at a very high intensity, your muscles run out for stored sugar long before your blood volume is reduced, and you slow down from lack of muscle sugar before you slow down from reduced blood volume (Sports Medicine, April- May 2007).

Fuel for muscles comes from sugar and fat stored in muscles, sugar and fat in the bloodstream and, to a lesser degree, protein. When you start to exercise intensely, more than 50 percent of your energy comes from sugar stored in muscles. Two hours later, most of the sugar stored in muscles is used up and less than 10 percent of energy comes from that source. If you do not supply extra sugar during exercise so that your muscles will use less of their stored sugar, muscles run out of glycogen and your performance will suffer. More on hyponatremia

Low vitamin D prevents insulin response; sunlight may not be enough

A recent study from the University of Wisconsin Osteoporosis Clinical Research Program in Madison, showed that some people have very low levels of vitamin D in spite of getting a lot of sunlight where they live in sun-drenched Hawaii (Journal of Clinical Endocrinology & Metabolism, June 2007).
The 93 participants in the study averaged 22.4 hours per week outside without sun screen. In spite of abundant sun exposure, 51 percent had low vitamin D levels.

Many people think of vitamin D as the vitamin that helps to prevent rickets, a disease characterized by weak bones that break easily. However, vitamin D does much more than that. It is necessary for your immune system to search out and destroy invading bacteria, viruses and even cancer cells. Recent studies show that lack of vitamin D prevents your body from responding to insulin adequately. The Third National Health and Nutrition Examination Survey shows that having low levels of vitamin D increases risk for high blood pressure, obesity, diabetes and having high blood levels of triglycerides (Archives of Internal Medicine, Volume 167, 2007). Researchers at Tufts University in Massachusetts showed that obesity increases a person's chances of having low vitamin D levels (Journal of Clinical Endocrinology & Metabolism, May 2007). A possible explanation is that fat sops up the available vitamin D so that it is not readily available to be used by the body.

Most people do not get adequate amounts of vitamin D from the food that they eat. They must depend on sunlight. People with dark skin require more sunlight to meet their needs for that vitamin, which could explain the increased risk for diabetes in dark-skinned people who live far from the equator. Calcium blocks the activation of vitamin D so people who take calcium supplements need to get extra sunlight or take vitamin D supplements. The large amount of calcium in milk can lower vitamin D levels even when the milk is fortified with the vitamin.

Vitamin D can be made in the skin when it is exposed to ultraviolet light from the sun. Then the liver converts vitamin D to an active hormone form called 25 hydroxy vitamin D. Then your kidneys convert this hormone to a more active di-hydroxy vitamin D. So you get that vitamin from your skin, liver and kidneys, and lack of sunlight and liver or kidney diseases can cause a deficiency. Now we learn that some people can be deficient even with adequate sunlight exposure and normal kidneys and livers. The only way to find if you are deficient of vitamin D is to get a blood test called 1,25 diyhxdroxy-vitamin D.