Gabe Mirkin, M.D.
The older you become, the more you need to exercise.
Researchers at Slippery Rock University of Pennsylvania
measured grip strength in older men at baseline and an average
of seven years later (Aging Male, September-December 2005).
The men squeezed a machine that measured the force that they
could exert. They lost 20 percent of their grip strength in seven
years. The older they were, the more they lost. Those who lost
the most height or weight, those on calcium channel blockers for
high blood pressure, and those who took in the most caffeine had
greater losses of strength. Loss of height is linked to
osteoporosis, which is associated with loss of muscle. High blood
pressure and unintentional weight loss indicate other health
problems. No explanation was offered for the association of
caffeine with loss of muscle strength.
These results are expected. Muscles are made of
millions of individual muscle fibers. A single nerve enervates
each fiber. With aging, a person loses nerve fibers that cause
loss of each connected muscle fiber. However, you can continue
to build strength in the remaining muscle fibers into your 90's and
beyond. Perhaps all people over 50 should get a stress
electrocardiogram as a screening test to see if exercise is likely
to harm them. If they pass the test, they should start or continue
an exercise program that includes some form of strength training
such as lifting weights or using strength-training machines.
June 15, 2006