Muscle-building insulin response restored with a 45-minute walk Senior Journal, May 30, 2007 GALVESTON - Why do older people tend to lose muscle mass and grow frail? One important factor identified by medical science is the reduced ability of the elderly to respond to the muscle-building stimulus of the hormone insulin. New research, however, shows this drop in insulin response in senior citizens can be modified by just moderate aerobic exercise. Insulin is best known for its link to diabetes - a condition in which either a complete lack of insulin or systemic resistance to the hormone's activity (as in type 2 diabetes) causes blood sugar levels to soar out of control. Recent studies have shown, however, that insulin also provides crucial assistance in building muscle, and that its ability to do so drops off dramatically in the elderly. Now, a small but provocative study by medical researchers in Texas and California suggests that a simple, cost-free therapy appears to largely overcome that drop-off in insulin response: moderate aerobic exercise such as walking. "We thought, let's see what happens if we use aerobic exercise, one of the interventions that has been shown in the past to improve vasodilation, to find out whether we can get insulin to stimulate muscle synthesis in older people," said UTMB professor Elena Volpi, senior author of a paper on the experiments appearing in the June issue of the journal Diabetes."It turned out that a fast walk restored the insulin response quite well."