Exercise is one of the best treatments for type 2 diabetes, promoting better cellular use of insulin, helping to maintain blood sugar levels in a healthy range, and also assisting cells in absorbing sugar.
However, if you are taking insulin or certain diabetes medications, exercise can make your blood sugar levels too low, a condition called hypoglycemia, and the following steps are taken to keep your blood sugar levels in a safe range.
Glucose testing before exercise
Take a blood glucose test before exercise. If your blood glucose level is between 100 and 250 mg/dl you can exercise, if it is below 100 mg/dl you will need to add a meal.
If you plan to exercise for a long period of time, such as 2 hours or more, do not start exercising until your blood glucose level is above 100 mg/dl.
If your blood glucose level is above 250 mg/dl, check your urine for ketone bodies, which are produced when fat, not sugar, is used as fuel to produce energy.
Do not start exercising if you have ketone bodies in your body; blood glucose levels may be higher, which can then lead to ketoacidosis and possibly coma or death.
Glucose testing during exercise
Glucose testing during exercise is not required unless you plan to exercise for 2 hours or longer, and should be performed hourly during prolonged exercise.
If the reading is low, such as 70 mg/dl or lower, stop exercising and add an appropriate meal, which should contain about 15 to 20 grams of fast-acting carbohydrates; try a small piece of fruit, a cup of low-fat yogurt, or a cup of oatmeal.
Check again 15 minutes later, and if the blood glucose level does not exceed 100 mg/dl, add another meal and test again 15 minutes later.
This may be a waste of time if you are participating in a race, however, if you continue to exercise, your blood glucose will continue to drop and may even drop to a dangerously low value.
Glucose testing after exercise
After exercise, test your blood glucose again. The blood glucose test will give you an idea of how exercise affects your diabetes, and will also let you know if you need to add a meal immediately (if your blood glucose is below 100 mg/dl) or if you can wait until your next meal or addition to eat again.
Blood glucose levels may drop after moderate or vigorous exercise for up to 24 hours, so it is important to have regular blood glucose testing.
Emergency treatment
The following quick-acting sugar sources are good for replenishing blood glucose when kept within easy reach:
- The following quick-acting sugar sources are good for replenishing blood glucose when kept within easy reach:
- Glucose tablets or gel.
- Plain soda (not sugar-free soda) or fruit juice.
- Sports drinks.
- 1 tablespoon of sugar.
- Read food labels to see how much food you need to consume to get 15 grams of carbohydrates.
- Never start exercising just as insulin is about to peak.
- Complete exercise at least 2 hours before bedtime.
- Do not drink before or after exercise.
- Do not drink alcohol before or after exercise.
- Stay away from hot tubs after exercise.
- Stay away from hot tubs, saunas and steam rooms after exercise.
- Physical exams once or twice a day.
- Delirium of consciousness or confusion.
- Blurred or impaired vision.
- Tingling or numbness of the mouth, lips, or tongue.
- Decreased coordination.
- Adjust insulin or medication, which is more effective if you want to lose weight.
- Increase intake before exercise.
- Change the type of exercise or the duration of exercise.
Other ways to avoid hypoglycemia
Use the following tips to help prevent hypoglycemia during exercise.
Do you have symptoms of hypoglycemia?
Low blood sugar is not always symptomatic, and it is very easy to miss the warning signs of low blood sugar when exercising, and may even mistake them for signs of good exercise: such as excessive sweating, rapid heart rate, feelings of fatigue, and hunger.
Test blood glucose if you notice any unusual symptoms, especially if the symptoms are inconsistent with exercise status, such as:
During exercise, hypoglycemia from exercising at night may make the sensation different than usual, or you may not have consumed enough food at meals for taking insulin; if in doubt, get a blood glucose test.
Persistent hypoglycemia levels during exercise
Some changes need to be made, discuss the following options with your doctor: