I have heard that one shouldn’t exercise if blood sugars are 100 mg/dl [5.6 mmol/L] or below. Does that mean any exercise or just exercise that is very demanding? My daily routine includes 10 to 15 minutes on an exercise bike as soon as I get up, before breakfast or medication. If my blood sugar is 100 mg/dl [5.6 mmol/L] or less, should I wait or can I go ahead and exercise? I exercise regularly, but 10-15 minutes on an exercise bike is hardly a marathon!

Those recommendations actually advise one to ingest added carbohydrate prior to exercise if blood sugar levels are less than 100 mg/dl [5.6 mmol/L], and those recommendations apply only to persons with diabetes using insulin or certain oral medications (sulfonylurea class or combinations of), which may place them at risk for exercise-induced low blood sugar. Testing before and after exercise to pattern your own blood sugar response to the activity will allow for more appropriate, individualized recommendations.

In your particular situation, light to moderate early morning exercise, prior to medications or breakfast, may be a great choice, as people with diabetes tend to be more insulin resistant and, therefore, less likely to experience low blood sugar in the dawn/early morning hours. I would encourage you to test pre and post exercise, to get a feel for what your particular exercise session does to your blood sugar. If you have never experienced low blood sugar during or after exercise, continue with your current practice. It is true that you may see a more dramatic blood sugar lowering effect with exercise of a longer duration or greater intensity, however it is important to recognize that any exercise, even low level physical activity will have a beneficial effect on blood sugar management. Also, it is important to remember that the blood sugar lowering effects of exercise can continue for hours after an exercise session.

DMW