Even at advanced age, exercise boosts muscle cells’ energy centers
(16 August 2009: VIDYYA MEDICAL NEWS SERVICE) -- Whether a person is 8 years old or 88, exercise helps protect against type 2 diabetes. It does this, in part, by revving up the function of small structures called mitochondria, which are found inside cells.
Diabetes specialist Nicolas Musi, M.D., associate professor in the School of Medicine at The University of Texas Health Science Center at San Antonio, is studying the effects of exercise on 100 muscle biopsy specimens and is documenting how exercise affects the mitochondria. Mitochondria function as “energy factories” by taking up different nutrients and converting them into energy.
“With age, there is a decline in the number and function of the mitochondria,” said Dr. Musi, also of the Barshop Institute for Longevity and Aging Studies at the UT Health Science Center. “We did an exercise intervention in older individuals and noticed that physical activity improves mitochondrial function substantially in people over 65.”
Gauge the amount of exertion
Exercise benefits people at any age. “While the benefits are related to the amount of exercise, in general, any amount of exercise is better than none,” Dr. Musi said. “Even small amounts of exercise can confer benefits. However, it is important to design an exercise program that will not cause harm, particularly in older persons or those compromised by conditions such as heart disease. If an older person has not done regular exercise for several years, it is best to begin a new exercise program under the supervision of a physician or certified trainer.”
Age-related decline in the number of mitochondria contributes to type 2 diabetes, but exercise can reverse it. “Older patients have a high incidence of diabetes and pre-diabetes, but respond very well to exercise,” Dr. Musi said. “We are investigating how physical activity can prevent diabetes in people who have pre-diabetes.”
A possible answer
With exercise, the muscle becomes more efficient at burning sugars and fats, Dr. Musi said. Scientists don’t know why, but one hypothesis is that exercise activates an enzyme called AMP kinase. This enzyme monitors energy levels and maintains normal levels of energy in cells.
“Further study will help us understand how exercise works to improve our health,” Dr. Musi said. “Also, by doing research in exercise, perhaps we can develop medications in the future that work like exercise. These could be used to help people who cannot exercise, and to maximize the benefits of exercise for those who can.”
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