Workouts boost insulin function

Sedentary older people at risk of developing diabetes show significant improvement in insulin resistance and the function of their insulin-making beta cells after just one week of exercise. Beta cell function is known to decline with age, although it is not clear why. As people age, they may also become less sensitive to the blood sugar-regulating effects of insulin and develop impaired insulin secretion. And while short-term exercise boosts insulin sensitivity, it is not clear how it might affect beta cell function. To investigate, American researchers made 12 sedentary individuals aged 60 and older perform an hour-long aerobic workout every day for a week. The exercise sessions, consisting of stints on a treadmill, exercise bike and cross-training machine, required study participants to work out at 60 percent to 70 percent of their maximum heart rate capacity. It was found that after the exercise period, study participants' sensitivity to insulin had increased by 53 percent, on average, while a measure of beta cell function called the disposition index had risen by 28 percent. However, there were no changes in their body weight, fat mass, levels of fat in the blood, or other factors that might explain the effect of exercise on beta cells. However, longer-term exercise training studies are required and are currently in progress to evaluate further exercise-training effects on beta cell function in age-related glucose intolerance.