Life-style activities such as walking are often recommended for patientswith type II (non-insulindependent) diabetes. Because many of these patientsare overweight and sedentary, such low-intensity activity would appear most appropriate, especially during initial intervention. However, there has beenlittle research on the effects of low-intensity life-style activity on glycemic control. This study examined the effects of varying the duration (0, 20, or 40 min) of low-intensity exercise (50–55% of age-predicted max heart rate)on glycemic responses during exercise and a subsequent meal in type II diabetic patients. Glycemic response to exercise was significantly related to the duration of activity; 20 min of activity decreased blood glucose (BG) by 6 mg/dl, whereas 40 min decreased BG by 16 mg/dl. The effect of exercise on glucose was maintained over a 30-min rest period but disappeared after a meal was consumed. Insulin and the insulin-to-glucose ratio were not affected by the length of activity. These data suggest that life-style activity of long duration (20–40 min) produces a significant, but modest, decrease in glucose levels in type II diabetic women.