Is there a best time to exercise? The short answer is yes: anytime you can fit it into your schedule. But exercise such as walking and moderate aerobics brings down blood sugar both while you do it and for up to a day afterward.
While that’s the big payoff, it’s also a potential hazard, especially if you take medication or insulin. The reason? Let’s say you’ve just taken oral medication or a dose of insulin to bring your blood sugar down, and then you immediately walk for an hour. The glucose-lowering combination of the treatment and the activity could send your blood sugar crashing.
On the other hand, if you’re taking insulin but don’t give yourself a large enough dose, your blood sugar may actually rise too high during exercise. That’s because when you’re physically active, the liver pumps out more glucose, and without adequate insulin, your body will have trouble shifting glucose from your blood to working muscles. Only you and your doctor can sort this all out, but you may be able to avoid most problems by following these guidelines.
- Exercise an hour or two after eating. At that point, your blood sugar levels are elevated from food, and you’ll have ample glucose to fuel your muscles. At the same time, your digestive system will have finished most of its work, so it won’t deplete the energy you need for your workout.
- If you take medication, ask your doctor if you can skip it before exercising or take a lower dose; the blood sugar drop from physical activity may be able to substitute for the drug. Otherwise, avoid exercising when the effects of your medication peak.
- If you use insulin, time your workouts so you’re not active when the effects of the insulin peak, often within the first hour or two after an injection. Your doctor will probably want you to monitor your blood sugar before and after to see how activity affects it, and based on those results, he may want you to adjust your insulin dose before you exercise.