NEW YORK, Jul 07 (Reuters) -- Regular exercise can lead to improved glucose (blood-sugar) tolerance in older adults -- which can reduce their risk of developing diabetes, according to researchers.
The effects of moderate levels of aerobic exercise are even more important in older people with high blood glucose levels (hyperglycemia) and insulin resistance, they report.
"Moderate-intensity aerobic training has a favorable effect on glucose tolerance," conclude investigators at Yale University School of Medicine in New Haven, Connecticut.
Glucose tolerance -- the ability of the body to regulate blood sugar levels -- decreases with age, but excess weight gain and decreased physical activity also play a role. Decreased glucose tolerance is believed to be a step in the development of type 2 (adult onset) diabetes. Since obesity has been linked to impaired glucose tolerance, many experts have assumed that only those exercise regimens which resulted in weight loss could bring the condition under control.
That may not always be the case, however. In the Yale study, published in the July issue of The Journal of the American Geriatrics Society, researchers placed 16 elderly men and women on a four month regimen of either aerobic exercise or non-aerobic yoga and stretching. Those in the aerobic exercise group were encouraged to walk and run on mini-trampolines equipped with handrails.
Those who participated in the non-aerobic regimen, four months of stretching and yoga, saw no changes in fitness level or glucose metabolism, according to a statement issued by the journal.
The four month aerobic regimen produced no "appreciable weight or fat loss" in elderly participants. However, blood tests revealed that people in the aerobic exercise group who had impaired glucose tolerance at the beginning of the study showed a 25% improvement in the way their body handled glucose.
The researchers also noted that blood levels of free fatty acids fell by 24% in the aerobic exercise group, leading the researchers to suggest that "training-related improvements in glucose regulation... may be modulated by decreases in (free fatty acid) concentrations."
The study team also conclude that "use of the mini-trampoline allows a safe, enjoyable, and effective mode of exercise for older people, who may otherwise be at risk for musculoskeletal injury from more traditional forms of weight-bearing aerobic exercise."
SOURCE: The Journal of the American Geriatrics Society 1998;46:875-879.
