In the clinical setting, the impact of educational efforts on the amount of regular exercise and its effects on diabetes control are unclear. Fifty type 1 diabetic, 50 type 2 diabetic and 70 non-diabetic subjects were evaluated using a questionnaire for type, duration and intensity of exercise to assess weekly energy expenditure. Diabetic subjects did not exercise more than controls: 36% of the type 1, 46% of the type 2 and 46% of the control subjects admitted no physical activity, and those exercising regularly had similar energy expenditure: 1808 +/- 320, 2722 +/- 617, 2523 +/- 304 (mean +/- SEM) kcal/week respectively (P = NS). There was no correlation between the degree of activity and HbA1c levels, or hypoglycaemic events. HbA1c levels were less than 6,8% in 31% of non-active patients versus 21% of active patients (P = NS). A negative correlation was found between physical activity and daily insulin usage (r = 0.27, P < 0.05), but differences between patients averaged only 4 IU/1000 kcal energy expenditure/day. We conclude that patients' attitude towards exercise was not improved by our educational methods and that physical exercise was not necessarily associated with good blood glucose control.