LOSS OF SKELETAL-MUSCLE MASS WITH AGING - EFFECT ON GLUCOSE-TOLERANCE

It is generally believed that aging results in glucose intolerance. Si nce skeletal muscle is the major site of glucose uptake following an o ral glucose tolerance test (OGTT), it is reasonable to hypothesize tha t loss of muscle mass with aging causes glucose intolerance, Evidence against this concept comes from extensive data demonstrating the usefu lness of the recommended procedures for performing an OGTT. This invol ves giving 75 g of glucose to all subjects regardless of body weight, and the criteria for categorizing glucose intolerance are the same for all individuals. That this works wed, with no evidence that larger pe ople have better glucose tolerance than smaller people, suggests thai muscle mass does not usually play a role. Recent studies on humans and rats indicate that aging per se does not result in glucose intoleranc e. In most of those older people with decreased glucose tolerance, thi s problem appears to be due to accumulation of abdominal fat with deve lopment of insulin resistance. We conclude that the loss of muscle mas s with aging does not usually result in glucose intolerance.