|
Low blood glucose after physical activity
A common cause of low blood glucose is too much physical activity without compensating for it. In fact, moderate-to-intense exercise may cause your blood glucose to drop for the next 24 hours. This post-exercise hypoglycemia is often referred to as the "lag effect" of exercise.
When you exercise, the body uses two sources of fuel to generate energy: glucose and free fatty acids--or fat. The glucose, stored in the body in a form called glycogen, comes from the blood, the liver, and the muscles. During the first 15 minutes of exercise, most of the glycogen is drawn from the bloodstream or the muscles. After 15 minutes of exercise, the body is fueled more by glycogen stored in the liver; and, after 30 minutes of exercise, by the free fatty acids.
The body will replace its depleted glycogen stores, but this process may take four to six hours, or even 12 to 24 hours when the physical activity has been intense. During this period, a person with diabetes is at higher risk for hypoglycemia--though there are precautions that can prevent it:
- Check your blood glucose before exercising to make sure your blood glucose is sufficient. If necessary, eat an appropriate snack.
- Avoid exercise at the peak of your insulin action.
- Avoid late-evening exercise. Exercise should be completed two hours before bedtime.
- Avoid alcohol before or immediately after exercise.
- Avoid hot tubs, saunas, and steam rooms directly after exercise. Otherwise, your heart rate will remain elevated longer, and your blood glucose may continue to drop.
- Check with your doctor about the length, intensity and duration of your planned exercise program.
- Check your blood glucose immediately after exercise to prevent low blood glucose from occurring hours after exercise. It may also be necessary to check your blood glucose more often for two to four hours after exercise. Intense exercise may cause your blood glucose to drop for the next 24 hours.
What should you do if you find your blood lucose is less than 100 mg/dl immediately after exercise?
- Follow post-exercise snack guidelines. If you are not scheduled for a snack or a meal for 30 to 60 minutes after exercise, 15 grams of carbohydrateshould be sufficient to prevent a low blood glucose. If no meal or snack is scheduled for more than one hour, take 15 grams of carbohydrateand 7 to 8 grams of protein.
- Increase carbohydrate intake before exercise.
- Decrease the dose of active insulin for the next exercise session.
- Consider decreasing the insulin dosage following exercise.
- If your blood glucose at bedtime is still less than 100 mg/dl, double your bedtime snack, or if possible, decrease your bedtime insulin dose.
|
