Topic Overview

You can safely exercise when you have diabetes. Here are some tips.

Before starting an exercise program

• Talk to your doctor about how and when to exercise. You may need to have a medical examination and tests (such as a treadmill test) before you begin. Also, some types of exercise can be harmful if you have complications from diabetes. Your doctor can tell you whether you need to avoid certain kinds of exercise.
• Choose a type of exercise that you like and that fits easily into your daily schedule. If you choose something you like, you will be more willing to continue the program. Try to include exercises that will work your heart and lungs and give you healthy muscles.
• Plan to exercise at about the same time and for the same length of time each day to help keep your blood sugar levels in the same range. If you want to increase your exercise, increase the intensity or the duration in small amounts.
• Have someone with you when you exercise, if possible. You may need help if your blood sugar level drops below a target range. And having a buddy can motivate you to keep going.

Starting a program

Start slowly so that you don't overdo it. Build up your exercise program bit by bit. Each week, try to do at least 2½ hours of moderate-to-vigorous intensity aerobic activity with no more than 2 consecutive days without exercise.^{footnote 1} It's fine to be active in blocks of 10 minutes or more throughout your day and week.

If your doctor says it's okay, do muscle-strengthening exercises 2 times a week and aim for 3 times a week.^{footnote 1} These exercises include push-ups and weight training. You can also use rubber tubing or stretch bands. You stretch or pull the tubing or band to build muscle strength. Be sure to work the major muscle groups: legs, hips, back, abdomen, chest, shoulders, and arms.

If you take insulin or other medicine for diabetes:

• Exercise changes the amount of glucose in your body. During vigorous exercise, the liver releases more stored glucose into the bloodstream. This raises blood sugar. When blood sugar is too high, it can lead to diabetic ketoacidosis. This can happen when you are very dehydrated.
  • If your blood sugar is over 16.7 mmol/L and you do not feel well, test for ketones. If you have ketones, do not exercise.
  • If your blood sugar is high (for example, over 16.7 mmol/L), you feel well, and you do not have ketones, exercise with caution.
• Watch for signs of low blood sugar.
  • If your diabetes is controlled by diet or medicine that does not lower your blood sugar, you do not need to eat a snack before you exercise.
  • Some medicines, such as glyburide, can cause low blood sugar emergencies. If you take that type of medicine or insulin, check your blood sugar before you exercise. If your blood sugar is less than 5.5 mmol/L, eat a carbohydrate snack first.
• Have some glucose or sucrose tablets or solution or other type of quick-sugar food with you when you exercise. You may have symptoms of low blood sugar while you exercise or up to 24 hours after you stop.
• Check with your doctor if you have been gradually increasing your exercise and have felt the symptoms of low blood sugar more than 2 or 3 times in one week. Your dose of medicine or insulin may need to be changed.

During exercise

• If you tend to get low blood sugar, exercise only after you have checked your blood sugar level.
• Wear shoes that fit well and polyester or blend (cotton-polyester) socks to keep your feet comfortable and to prevent blisters. Use silica gel or air midsoles in your shoes.
• Drink plenty of water before, during, and after you are active. This is very important when it's hot out and when you do intense exercise.
• Wear medical identification at all times. You can get medical identification, such as a bracelet, from a pharmacy or on the Internet.
• Carry glucose or sucrose tablets or solution or quick-sugar food with you while you exercise.

After exercise

Exercise can lower your blood sugar hours later. Test your blood sugar and have a plan for treating low blood sugar.

Adrenaline released with short bouts of vigorous exercise can cause high blood sugar. Combining short bursts of vigorous activity with longer moderate-intensive exercises can help prevent this problem.

For more information, see the topic Fitness: Getting and Staying Active.