How Exercise Prolongs Life by Making You Stronger

As you age, you become progressively weaker. If you exercise regularly, you will not become as weak as other people your age who do not exercise. The same mechanism that makes you stronger will also help you to live substantially longer than people who do not exercise.

Harvard researchers have proven that exercise prevents loss of the connections between nerves and the muscles that they enervate caused by aging (Proceedings of the National Academy of Sciences, published online August 29, 2010). The researchers studied genetically engineered mice with nerve cells that glow in fluorescent colors. Muscles are made up of millions of individual muscle fibers. Every muscle fiber is innervated by a single nerve. If the nerve dies, the muscle fiber innervated by that nerve also dies. With aging, all humans and mice lose nerves that cause their corresponding muscle fibers to die also. However, mice placed on just one month of exercise in later life actually regained some of the lost connections between nerves and muscle fibers. This is the same mechanism that helps revive nerves in the brain to slow down and even stop the loss of mental function associated with aging. Exercise also prevents loss of strength associated with aging that causes falls, broken bones and injuries in older people.

Researchers at The University of Western Ontario in London just reported that competitive runners with an average age of 65 had the same number of nerves and muscle fibers as younger recreational runners, and far more muscle fibers and nerves than non-exercising age-matched controls (Medicine & Science in Sports & Exercise, September 2010).

This helps explain why exercisers live more than 12 years longer than those who do not exercise (British Journal of Sports Medicine, March 2008). Many other studies show that lifelong physically active older mammals have greater numbers of muscle fibers and their associated nerves than comparable-age mammals that do not exercise. Intense exercise is far more effective than casual exercise to:
• Prevent and treat diabetes (Circulation, July 2008; J. Applied Physiology, January 2006)
• Prevent heart attacks in obese people without weight loss (MSSE, October 2006)
• Prevent heart attacks (MSSE, July 1997)
• Reduce belly fat (MSSE, November 2008)
• Prevent premature death (Heart, May 2003)
• Prevent metabolic syndrome and heart attacks (Exercise and Sports Sciences Reviews, July 2009)
• Raise HDL cholesterol (Journal of Strength and Conditioning Research, March 2009)
(Caution: Exercise can cause heart attacks in people with blocked coronary arteries.)