Influences of age and exercise on glucose metabolism: Implications for management of older diabetics

The well-characterized decline in glucose tolerance during aging is due primarily to impaired insulin-mediated glucose uptake in peripheral tissues. Elderly persons with reduced insulin sensitivity are predisposed to the development of noninsulin-dependent diabetes mellitus (NIDDM), which is common in the geriatric population. Numerous studies suggest that exercise and physical training increase insulin sensitivity in young adult and middle-aged nondiabetics, older subjects with impaired glucose tolerance, and middle-aged persons with NIDDM. These investigations provide presumptive evidence that elderly persons with NIDDM may benefit from exercise training, although no published studies have specifically addressed the effects of exercise in older diabetics. Physical activity may also be effective in preventing the development of NIDDM. In addition, exercise training improves several cardiovascular risk factors, such as plasma lipid abnormalities, hypertension, and obesity. The risks of exercise in older diabetics include hypoglycemia in insulin-treated patients, exacerbation of preexisting cardiovascular disease, and worsening of long-term diabetic complications. Any exercise prescription in the older diabetic must be individualized to the patient’s physical capabilities, limitations, and preferences.