Exercise:

Sedentary habits, especially watching TV, are associated with significantly higher risks for obesity and type 2 diabetes. Regular exercise, even of moderate intensity (such as brisk walking), improves insulin sensitivity and may play a significant role in preventing type 2 diabetes -- regardless of weight loss. An important study reported a 58% lower risk for type 2 diabetes in adults who performed moderate exercise for as little as 2.5 hours a week.

Aerobic Exercises. Aerobic exercise has significant and particular benefits for people with diabetes. Regular aerobic exercise, even of moderate intensity, improves insulin sensitivity. People with diabetes are at particular risk for heart disease, so the heart-protective effects of aerobic exercise are especially important. Moderate exercise protects the heart in people with type 2 diabetes, even if they have no risk factors for heart disease other than diabetes itself. (In general, patients with diabetes should aim for a heart rate target of 55 - 85% of their maximum heart rate when exercising.)

Strength Training. Strength training, which increases muscle and reduces fat, may also be helpful for people with diabetes.

Some Precautions for People with Diabetes Who Exercise. The following are precautions for all people with diabetes, both type 1 and type 2:

• Because people with diabetes are at higher than average risk for heart disease, they should always check with their doctors before undertaking vigorous exercise. For fastest results, frequent high-intensity (not high-impact) exercises are best for people who are cleared by their doctors. For people who have been sedentary or have other medical problems, lower-intensity exercises are recommended.
• Strenuous strength training or high-impact exercise is not recommended for people with uncontrolled diabetes. Such exercises can strain weakened blood vessels in the eyes of patients with retinopathy. High-impact exercise may also injure blood vessels in the feet.

Patients who are taking medications that lower blood glucose, particularly insulin, should take special precautions before embarking on a workout program:

• Monitor glucose levels before, during, and after workouts (glucose levels swing dramatically during exercise).
• Avoid exercise if glucose levels are above 300 mg/dl or under 100 mg/dl.
• Inject insulin in sites away from the muscles used during exercise; this can help avoid hypoglycemia.
• Drink plenty of fluids before and during exercise; avoid alcohol, which increases the risk of hypoglycemia.
• Insulin-dependent athletes may need to decrease insulin doses or take in more carbohydrates prior to exercise, but may need to take an extra dose of insulin after exercise (stress hormones released during exercise may increase blood glucose levels).
• Wear good, protective footwear to help avoid injuries and wounds to the feet.

Some blood pressure drugs can interfere with exercise capacity. Patients who use blood pressure medication should consult their doctors on how to balance medications and exercise. Patients with high blood pressure should also aim to breathe as normally as possible during exercise. Holding the breath can increase blood pressure. [For more information, see In-Depth Report #29: Exercise.]

Stress Reduction

Chronic stress has been associated with the development of insulin resistance, a primary factor in diabetes. Stress can also worsen existing diabetes by impairing the patient's ability to manage the disease effectively. Stress-relieving techniques include meditation, biofeedback, relaxation response, and yoga. One study reported that yoga helped patients with type 2 diabetes reduce their need for oral medications. Studies have also indicated that yoga and Tai Chi (an ancient Chinese exercise involving slow relaxing movements) may lower blood pressure almost as well as moderate-intensity aerobic exercises. [For more information, see In-Depth Report #31: Stress.]