DR. MIRKIN: LOSING MUSCLE WITH AGING
Muscle Loss with Aging
By Gabe Mirkin, M.D.
Competitive masters athletes, 40 to 81 years old, who trained four to five times per week did not lose any muscle size or significant strength with aging (The Physician and Sportsmedicine, October 2011;39(3):172-8).
This shows that loss of muscle size and strength in older people is caused by lack of exercise, not just with aging.
The athletes did gain fat in spite of exercising. Those in their 70s had almost as much strength and thigh muscle size as those in their 40s.
MOST PEOPLE LOSE MUSCLE
Recent studies show that after age 40, men lose more than eight percent of their muscle size each decade, and this loss of muscle increases after age 70.
The people who lose the most muscle are usually the ones who die earliest. They are also most at risk for falls and broken bones.
HOW EXERCISE PREVENTS MUSCLE LOSS WITH AGING
Muscles are made up of thousands of individual muscle fibers. Each muscle fiber is innervated by a single nerve. With aging, humans lose the nerves that innervate muscle fibers, and with each nerve loss, they lose the associated muscle fiber so muscles become smaller.
We used to think this happens because of aging. However, this new study and others show that lifelong competitive athletes do not lose the nerves that innervate their muscles with aging. They retain the nerves and therefore retain most of the muscle fibers that they would have lost if they were inactive.
MESSAGE
If you exercise regularly, continue to do so. If you don’t, check with your doctor and then get instructions on how to start an exercise program.
INTENSE EXERCISE GIVES MORE HEALTH BENEFITS THAN JUST EXERCISING
Intense exercise is even more effective than just exercising in prolonging life and preventing disease. A study from Norway shows that the more fit you are, the fewer heart attack risk factors you have and the less likely you are to develop diabetes (Medicine & Science in Sports & Exercise, August, 2011;43 (8):1465).
VO2 PEAK
The authors measured level of fitness by a test called VO2 peak: the highest amount of oxygen a person can use in an all-out exercise test. It is a direct measure of a person’s fitness, and the more intensely a person exercises, the greater the increase in VO2 peak. Intensity of exercise is far more important than duration in determining peak oxygen uptake.
Women whose fitness values were low (VO2 peak < 35.1 mL kg- 1 min-1) were five times more likely to have heart attack risk factors compared to those whose fitness was high (VO2 peak (< 40.8 mL kg-1 min-1). Men with low fitness (44.2 mL kg-1 min-1) were eight times more likely to have heart attack risk factors than those with high fitness ((50.5 mL kg- 1 min-1).
Furthermore, those who changed from low to high intensity training had substantially higher VO2 peak at follow-up compared with people whose activity remained low.
Dr. Pinna says:
Although, supposedly, trained athletes do not lose muscle mass with aging, all my patients do. It seems inevitable. Since the muscle loss is tied to nerve loss, then the thing to do is use your nerves; both in your brain as in your body.
Worse than muscle loss is the loss of the ability to think and to appreciate the world around you.
Exercise helps to prevent both areas of loss, since you must be alert in order to participate in sports or even to do simple mechanical exercises such as lifting weights.
The bottom line is that old adage: Never give up! Whether you’re in a battle or battling your belly, stick to it!
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