Physical activity or exercise has been considered fundamental in the treatment of diabetes along with diet and medication. Of greatest concern to many exercisers is the risk of hypoglycemia. In individuals whose diabetes is being controlled by lifestyle alone, the risk of developing hypoglycemia during exercise is minimal, making stringent measures unnecessary to maintain BG. But in insulin or insulin secretagogue users, severe hypoglycemia cause the fatal condition. Precipitating factors for severe hypoglycemia are missed or delayed meal, increased physical activity, incorrect insulin dose and alcohol use, etc. Increased physical activity in diabetic patients induce different features of hypoglycemia according to aerobic or resistance, intensity, duration and time of exercise, user of insulin or insulin secretagogues and underlying conditions. On the other hands, insulin type, food or snack and recent hypoglycemia are considered, too. In this session, I will show the pathophysiology of hypoglycemia caused by exercise in diabetic patients and different features according to type, duration, time or underlying diseases. Is there any different effect on the glucose-lowering from moderate vs. intermittent high intensity exercise? And I will suggest the solutions which prevent or minimize hypoglycemic state. Finally, I will discuss about the in-home randomized trial to assess the efficacy and safety of a continuous glucose monitor-based overnight predictive low-glucose suspend (PLGS) system, recently reported.