The Importance of Exercise

If you have diabetes, consult your doctor before starting or changing a fitness routine. This is especially important if you are overweight or have a history of heart disease, peripheral vascular disease, or diabetic neuropathy. Your doctor may recommend a stress test to make sure it’s safe for you to exercise and to determine the intensity that’s best for you. You may also need special footwear to protect your feet (see "Foot and vision problems" below).

Exercise doesn’t have to be strenuous to be beneficial, but try to spend at least 30 minutes a day engaged in some physical activity. While one person may prefer walking, another may choose something more vigorous, such as biking, swimming, or even running a marathon, provided his or her doctor approves.

In general, the best time to exercise is one to three hours after eating, when your blood sugar level is likely to be higher. If you use insulin, it’s important to test your blood sugar before exercising. If the level before exercise is below 100 mg/dL, eating a piece of fruit or having a small snack will boost it and help you avoid hypoglycemia. Testing again 30 minutes later will show whether your blood glucose level is stable. It’s also a good idea to check blood sugar levels after any particularly grueling workout or activity. If you’re taking insulin, your risk of developing hypoglycemia may be highest 6–12 hours after exercising.

Because of the dangers associated with diabetes, always wear a medical alert bracelet indicating that you have diabetes and whether you take insulin. Also keep hard candy or glucose tablets with you while exercising in case your blood sugar drops precipitously.

Foot and vision problems
Properly fitting footwear is necessary for anyone who exercises regularly, but it’s even more important for people with diabetes, who are more likely to have nerve damage that can affect their feet. This nerve damage can result in peripheral neuropathy, which may make your feet less sensitive to irritation and pain. As a result, you may not be aware of the discomfort of ill-fitting shoes, or you may not realize that you have suffered a foot injury, allowing the situation to worsen. Diabetes can also impair your circulation, impeding your natural healing capacity and your ability to fight infection. Fortunately, if you are diabetic and want to exercise, you can take special precautions to protect the health of your feet (see
Putting Your Best Foot Forward). If you have severe diabetic eye disease, don’t begin exercising without permission from your doctor. If you have active retinopathy, your doctor may discourage you from participating in high-impact sports (jogging, diving, boxing), since they may precipitate bleeding into the eye.