Whether you already have diabetes or want to avoid it, you have every reason to be physically active. If you have diabetes, though, and particularly if you need insulin to control it, vigorous exercise requires some special efforts to make sure your exercise program is safe.
Your working muscles use up glucose at a rate 20 times greater than usual. And if you’re not taking insulin, your insulin levels also drop, so you’re not at risk of either high or low blood sugar. If you have mild or moderate diabetes, you’re doing precisely what you need to keep your disease under control.
Following very intense exercise, however, stress hormones could cause a temporary spike in blood sugar–a possible risk for some persons with diabetes. Your doctor may want you to check your blood sugar at this time. There are other possible hazards, depending on the seriousness of the disease, but there is no question that regular exercise is good for diabetes.
If you’re planning to get started, you should talk to your doctor first. A physical examination may be needed to assess the type and severity of complications, particularly those involving small and large blood vessels or peripheral nerves in the legs and feet.
Mild to moderate aerobic activity is ordinarily recommended for type 2 diabetics because of its stabilizing effect on blood sugar, often sustained for some time after exercise. Aerobic activities include brisk walking, swimming, biking and running. Compared to competitive sports such as soccer or basketball, these activities allow you to better control the intensity.
Because of lack of sensitivity to pain, persons with neuropathy have to be careful about developing sores on the feet that could lead to serious complications. Long distance running could be risky; non-weight-bearing exercise is usually recommended.
The other staple workout for diabetics is strength training. In one study, Hispanic men and women who performed resistance training for 16 weeks showed impressive improvement in blood sugar control. About 70 percent were able to decrease their diabetes medications as a result.
Patients with severe diabetic eye disease may have to avoid heavy weight lifting that causes straining and an increase in blood pressure.
A secondary analysis of results from the HART-D trial confirmed that “optimal benefits” occur with the combination of aerobic exercise and strength training. In this study, the regimen was 110 minutes a week of aerobics and 30 minutes lifting weights. Subjects who developed increased fitness and reduced waist circumference as a result of this exercise regimen were 2.81 times more likely to have lower blood sugar levels and reduced medication for their type 2 diabetes.
Regularity is important. The beneficial glucose-lowering effects and improved insulin sensitivity resulting from exercise deteriorate within 72 hours of the last session. Take a day off, or even two, but not three in a row.
If you are taking insulin or other medications that can lower blood sugar, you need to follow some guidelines to assure a safe blood sugar level.
BEFORE EXERCISE: Test your blood sugar 30 minutes before exercising. If your level is between 100 and 250 mg/dL, you’re safe to exercise, but if it’s lower than 100 mg/dL, you need to boost your blood sugar with a small carbohydrate snack such as fruit or crackers. A reading higher than 300 mg/dL indicates that you’re at risk of ketoacidosis and should postpone your workout.
Never work out when you have ketones in your urine or your blood as this can make your blood sugar spike even higher.
DURING EXERCISE: If your workout goes longer than 30 minutes you probably need to test your blood sugar again, particularly if you’re starting a new activity or changing intensity or duration. If your blood sugar drops below 70 mg/dL or if you feel shaky, nervous or confused, stop immediately and eat or drink something (such as glucose tablets, hard candy, fruit juice or non-diet soda) to raise your glucose level.
Then re-check your blood glucose every 15 minutes until your blood sugar reaches and stays at a safe level.
AFTER EXERCISE, you need to check your blood glucose immediately and again several times during the next few hours until you are sure that it is stable. The longer and more strenuous your workout, the longer you are at risk of hypoglycemia (low blood sugar).
Diabetics know the dangers of letting blood glucose get too high or too low. They do not always know the wide-ranging benefits of exercise. While physical activity can temporarily complicate good blood glucose control for some patients, that’s no reason to stay on the couch.
REFERENCES:
Ann Albright, Ph.D., R.D., et al, “Exercise and type 2 diabetes,” Medscape, February 9, 2010.
Jeanine R. Albu, et al, “Metabolic changes following a 1-year diet and exercise intervention in patients with type 2 diabetes,” Diabetes, 2010;59(3):627-633.
Barbara Bushman, Ph.D., FACSM, “Diabetes and physical activity,” American College of Sports Medicine.
Marlene Busko, “Aerobic exercise plus resistance training best for diabetes,” Medscape Medical News, May 23, 2013.
Sheri R. Colberg, Ph.D., FACSM, et al, “Exercise and type 2 diabetes: the American College of Sports Medicine and the American Diabetes Association joint position statement,” Diabetes Care, December, 2010.
Mayo Clinic Staff, “Diabetes and exercise: when to monitor your blood sugar,” MayoClinic.com, February 24, 2011.
National Diabetes Information Clearinghouse, “What I need to know about physical activity and diabetes,” NIH Publication No. 13-5180, November 2012.
National Library of Medicine, “Diabetes and exercise,” MedlinePlus, updated September 4, 2012.
N.S. Pierce, “Diabetes and exercise,” British Journal of Sports Medicine, July 12, 2013.
Lara C. Pullen, Ph.D., “Diabetes patients reduce visceral fat, using exercise alone,” Medscape Medical News, June 26, 2013l.
Miriam E. Tucker, “Hypoglycemia exceeds hyperglycemia admissions for elderly,” Medscape Medical News, July 1, 2013.
“Type 2 diabetes and exercise,” WebMD Medical Reference, reviewed by Melinda Ratiri, D.O., M.S., May 27, 2013.
09/16/2013
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