Exercising With Diabetes

Tips, Strategies, and Precautions

Russell D. White, MD, with Carl Sherman

Series Editor: Nicholas A. DiNubile, MD

THE PHYSICIAN AND SPORTSMEDICINE - VOL 4 - NO. 27 - APRIL 1999

If you have diabetes, one of the best things you can do for yourself is to stay—or begin to be—active. A regular exercise program can help stabilize your blood sugar, reduce your need for insulin and medication, and keep your weight under control. Diabetes increases the risk of heart disease, but exercise can lower it. Best of all, exercise helps you get more out of life.

Because of some of the risks of your disease, however, it is important to consult your doctor before starting an exercise program. He or she may want to conduct a thorough physical exam to help you design a safe, pleasurable program. You may need a stress test to evaluate your heart and to determine the best level of exercise for you.

What Activities?

The activities most likely to help control your disease and reduce the risk of heart disease are aerobic—exercises such as walking, jogging, biking, or swimming that you do strenuously enough to raise your pulse and make you breathe harder. You'll get maximum benefits if you participate in 30 minutes or more of such activities at least three times a week. In addition, strength training (weight lifting) can also help improve fitness and heart health.

If you haven't been active, build up to this level slowly. Start by walking 5 minutes a day, at a comfortable pace. Increase the length and speed of your walk as you feel stronger.

And remember: Any exercise is better than none. Physical activity built into your day—taking the stairs instead of the elevator, parking at the far end of the lot for a longer walk to your office—helps to satisfy your need for exercise.

Which exercise? Choose a sport or activity you will enjoy doing regularly. But some activities may not be suitable:

• If you become dizzy or lightheaded when exercising in an upright position, swimming or biking are better than hiking or jogging.
• People who have retinopathy should avoid activities that sharply raise blood pressure, such as weight lifting.
• If you have poor sensation in your feet, take special care to choose proper footwear (see below), and consider low-impact exercise (swimming, biking, or rowing) rather than walking or jogging.
• Activities like scuba diving and rock climbing can be dangerous if there's any possibility of hypoglycemia (low blood sugar).
• Lifting weights can complement an exercise program nicely. However, most people who have diabetes should use light weights and lift them 12 to 15 times for each exercise, rather than lift heavy weights just a few times.

Staying Safe

Prevent injuries by warming up before exercise with 5 to 10 minutes of moderate activity and then stretching, and by cooling down slowly for 5 to 10 minutes after exercise. Walking at a medium pace is a good warm-up or cool-down activity.

Exercise changes your body's metabolism in healthful ways (for example, it increases the rate at which you burn glucose for fuel). But you must take steps to regulate the process properly. Planning for trouble-free activity with the help of your doctor may include these steps:

• Check your blood sugar levels before and after workouts and every 20 to 30 minutes during prolonged exercise. (Many activities burn 500 to 600 calories an hour!) If your blood sugar is under 100 mg/dL, take a snack containing 15 to 30 grams of carbohydrate before you exercise. If your blood sugar is excessive (over 250 mg/dL for people with type 2 diabetes; over 200 mg/dL for those with type 1), postpone exercise until you bring it down.
• Know the signs of hypoglycemia (for example, dizziness, sweating, trembling, double vision), and have a snack ready if they occur.
• Exercise 1 to 2 hours after a meal.
• Avoid exercise at times of peak insulin activity. Morning exercise is ideal. People who have type 1 diabetes should avoid evening exercise, if possible.
• Adjust your insulin dosage, if necessary. (Follow your doctor's advice, but this usually means reducing the dose of short-acting insulin before exercise.)
• Patients who take oral antidiabetic drugs may need to change their dosages. Follow your doctor's advice.
• After prolonged or intense exercise, you may need extra carbohydrate foods for up to 24 hours to refill muscle starch reserves. Keep in mind that it takes 550 grams of carbohydrate to restore glycogen levels after a glycogen-depleting activity, such as endurance running or cycling. Beware of delayed hypoglycemia!
• Drink lots of fluids: about a pint 2 hours before exercise, and enough fluid to replace what you sweat away during a long workout.
• Wear shoes that fit well, have cushioned midsoles (silica gel or air), and have a toe box that is comfortably wide and longer than your longest toe. Socks should also fit well and should be made of a material that wicks moisture away to keep your feet dry.
• Avoid alcohol around the time of exercise (even the night before a morning workout).
• Wear a Med-Alert or similar identification bracelet or tag where it can be seen easily.
• Know yourself. Become aware of your own pattern of blood-glucose response to exercise.

Making It Fun

If exercise is going to do you good, you need to keep at it—so it needs to be a pleasure, not a burden. Many people find it most enjoyable to work out with others—a friend or a group that takes regular morning walks, for example. Also, you're less likely to skip sessions if someone is depending on you.

Finding a pleasant setting for exercise will also help keep you motivated. Try a park near work where you can walk, or find a clean, attractive health club.

If your schedule is tight, make exercise time productive: Prop your newspaper up on your stationary bike, or park your treadmill in front of the TV so you can watch the early-morning business report.

And remember: Exercise is a way of life—enjoy it!

Information Sources for Active Patients With Diabetes

Here are some resources for people who have diabetes and want to know more about exercise:

• The American Diabetes Association's site on the World Wide Web has an exercise section (http://www.diabetes.org/exercise/) featuring frequently asked questions, a monthly profile of an active person with diabetes, articles on exercise and diabetes, and information on ADA-affiliated biking and walking events. The ADA's phone number is (800) 342-2383.
• The Web site of the International Diabetic Athletes Association (http://www.diabetes-exercise.org) offers information about membership, which includes a quarterly newsletter. The site also offers information on regional chapters and association events. The association's phone number is (800) 898-4322.
• MiningCo.com (http://home.miningco.com/index.htm), a commercial Web site that evaluates other Web sites, offers an extensive and up-to-date listing of links on exercise and diabetes in its health and fitness section. Topics range from exercise and insulin to exercise resources for people who have limited mobility.

Remember: This information is not intended as a substitute for medical treatment. Before starting an exercise program, consult a physician.

Dr White is associate director of the family practice residency and director of the sports medicine fellowship program at Bayfront Medical Center in St Petersburg, Florida. He has had type 1 diabetes for 40 years without complications. He regularly jogs or bicycles 3 to 4 days a week, varying his activity to prevent boredom, and occasionally goes on 4- to 5-hour group cycling treks. Mr Sherman is a freelance writer in New York City. Dr DiNubile is an orthopedic surgeon in private practice in Havertown, Pennsylvania, specializing in sports medicine and arthroscopy.