Exercise can prevent the onset of diabetes, particularly in those most at risk of contracting the disease.
A California study of 202 men over 24 years found that the more a man engaged in regular, leisure time exercise, such as walking, stair climbing or sports, the less likely he was to develop non insulin dependent diabetes.
For each energy expenditure of 550 kcal, for instance, the age adjusted risk of NIDDM was reduced by 6 per cent.
Nevertheless, any benefit was weakened by weight gain.
The protective effect of exercise was strongest in those at high risk of developing diabetes: the obese, the hypertense or those with a family history of diabetes.
Although researchers aren't clear why this should be so, regular exercise seems to improve long term glucose control, besides keeping weight down and improving hypertension.