Exercise Prescription and Diabetes
By Dr. Neda Amani
Physicians and exercise professionals working together can help people with type 2 diabetes be active for life.
The internationally-operated Gold’s Gym launched a national effort in 2006, in partnership with the American Diabetes Association, to fight diabetes with fitness. Gold’s launched a special diabetes fitness centre on its website that provides free information on how to start and maintain a fitness program if you are affected by diabetes.
To most experts in the fitness industry who work with obese clients with diabetes or who are at risk of diabetes, the Gold’s initiative may appear to be not only intuitive but well overdue. Obesity is reaching epidemic proportions, (over 60% of Canadians are obese or overweight), and the rate of diabetes is following close behind.
There is a greater need than ever before for exercise professionals to work with healthcare providers, particularly physicians, to better prevent and manage type 2 diabetes.
Diabetes Statistics and Burden of Illness
More than two million Canadians have diabetes and by the end of the decade, this number is expected to rise to three million.
Approximately 10% of people with diabetes have type 1 diabetes. The number of people with type 2 diabetes has been increasing dramatically due factors including rising rates of obesity, an aging population and increasingly sedentary lifestyles.
The personal costs of diabetes may include a reduced quality of life and the increased likelihood of complications such as heart disease, stroke, kidney disease, blindness, amputation and erectile dysfunction. The financial burden of diabetes and its affect on people with the disease and the healthcare system is enormous. Based on a U.S. study, diabetes and its complications cost the Canadian healthcare system an estimated $13.2 billion every year. By 2010, it's estimated that these costs will rise to $15.6 billion a year and by 2020, $19.2 billion a year.
Prevention of Type 2 Diabetes
Type 2 diabetes is defined as a fasting plasma glucose level of 7.0 mmol/L or higher. A fasting plasma glucose test determines how much glucose is in the blood. Patients with impaired glucose tolerance (IGT), sometimes called pre-diabetes, have blood glucose levels of 6.1 to 6.9, which are higher than normal (3.5 to 6), and are at high risk of developing type 2 diabetes. There have been large, well-designed studies assessing lifestyle and pharmacological interventions to prevent the progression from IGT to diabetes.
Lifestyle Change Trumps Pharmacologic Intervention
The Finish Diabetes Prevention Study and Diabetes Prevention Program (DPP) both looked at the effects of dietary modification (a low-calorie diet with reduced fat intake) and moderate-intensity physical activity (minimum 150 minutes per week). Both these studies lead to an approximate weight loss of 5% to 7% of participants’ initial body weight and showed a 58% risk reduction for type 2 diabetes at four years. In people over 60, the risk was cut by almost 71%.
The drug metformin was used in a second arm of the DPP. A dosage of 850mg twice daily for an average of 2.8 years significantly decreased progression to diabetes by 31%.
In the Study to Prevent Non Insulin Dependent Diabetes Mellitus, 100mg of Acarbose, taken three times daily, showed an overall 30% reduction in risk of progression to diabetes in a five-year study with a mean follow-up of 3.3 years
Summary of 2003 CDA Clinical Practice Guideline Recommendations for Prevention of type 2 diabetes
- In individuals with IGT, a structured lifestyle modification that includes moderate weight loss and regular physical activity should be implemented to reduce the risk of type 2 diabetes.
- In individuals with IGT, pharmacologic therapy with Metformin (biguanide) or Acarbose (alpha-glucosidase inhibitor) should be considered to reduce the risk of type 2 diabetes.
Management of Type 2 Diabetes
There is clear evidence showing improved glycemic control in adults with type 2 diabetes who are involved in a supervised program involving aerobic and resistance exercise. Moderate to high levels of physical activity also helps to prevent the serious complications of diabetes such as vascular disease of the brain, heart, kidney, eyes and legs by improving glycemic control, decreasing insulin resistance, improving abnormal blood lipid patterns, reducing hypertension and helping with weight control.
Summary of 2003 CDA Clinical Practice Guideline Recommendations for the Management of type 2 diabetes
1 In people with type 2 diabetes, if glycemic targets are not achieved using lifestyle management within two to three months, antihyperglycemic agents should be initiated. In the presence of marked hyperglycemia (Hemoglobin A1C ³9.0%), antihyperglycemic agents should be initiated concomitant with lifestyle counselling.
2 In type 2 diabetic patients, if individual treatment goals have not been reached with a regimen of nutrition therapy, physical activity, sulfonylurea, sulfonylurea plus metformin or other antihyperglycemic agents, insulin therapy should be initiated to improve glycemic control.
Exercise Considerations In People With Diabetes
Patients with diabetes should first be informed that regular exercise is a key part of their treatment plan.
Before beginning a physical activity more vigorous than walking, people should be assessed by their physicians for conditions that might contraindicate certain types of exercise, or predispose them to injury (e.g., severe autonomic neuropathy, severe peripheral neuropathy, preproliferative or proliferative retinopathy) or be associated with increased likelihood of cardiovascular disease (CVD). For previously sedentary individuals with diabetes at high risk for CVD, an exercise stress test is recommended before they begin exercise more vigorous than brisk walking and, particularly, before they start resistance training.
To start, previously sedentary individuals should gradually build up their exercise with as little as five to ten minutes per day. Multiple, shorter exercise sessions lasting at least 10 minutes each is as effective as a single longer session of equivalent length and intensity.
Brisk walking is the most popular and most feasible type of aerobic exercise for most overweight, middle-aged and elderly people with diabetes. For most middle-aged individuals, moderately brisk walking, cycling or swimming are examples of moderate aerobic exercise, while brisk walking up an incline or jogging is considered vigorous aerobic exercise. Resistance exercise performed two or three times per week has shown to be particular beneficial as it increases the resting metabolic rate by increasing muscle mass which also results in increased overall strength and sense of well being. The studies reporting the greatest impact of resistance exercise on Hemoglobin A1C (indicator of average blood glucose levels over a three-month period) have had patients progress to three sets of approximately eight resistance-type exercises at a moderately high intensity (eight repetitions at the maximum weight that can be lifted eight times), three times per week.
Exercise professionals can also ask clients see their physicians regularly to monitor their blood glucose and lipid levels, blood pressure and Hemoglobin A1C profiles. This helps patients to see firsthand the positive medical effects of their newly-active lifestyle and also helps motivate them. Patients and exercise professionals also need to be aware of the positive changes occurring to their blood glucose and lipid levels so they can reduce their diabetes and cholesterol medications, if need be, and thereby avoid hypoglycemia and unnecessary pharmacologic treatment.
Patients should regularly monitor their blood glucose and have a snack if it falls below 3.5 mmol/L. During physical activity, patients should drink early and frequently to compensate for losses from sweating or drink the maximum amount of fluid that can be tolerated. Dehydration can have adverse effects on cardiac function and blood glucose levels. It is imperative that patients who are at high risk of hypoglycemia wear a clearly-visible diabetes identification bracelet while exercising.
Summary of Recommendations for Exercise Prescription in Diabetic Patients
1. An exercise ECG stress test should be considered for previously sedentary individuals with diabetes at high risk for CVD who wish to undertake exercise more vigorous than brisk walking.
2. People with type 2 diabetes should accumulate at least 150 minutes of moderate-intensity aerobic exercise each week spread over at least three non-consecutive days or, if willing, accumulate ≥4 hours of exercise per week.
3. People with diabetes (including elderly people) should perform resistance exercise three times per week.
Complications of Exercise in the Diabetic Patient
Exercise can lead to several other complications besides hypoglycemia. Risks of exercise may include exacerbation of previously undiagnosed underlying cardiovascular disease with the development of angina pectoris, myocardial infarction or cardiac arrhythmias. Patients with proliferative retinopathy are at risk for retinal or vitreous hemorrhage or retinal detachment when they engage in extremely strenuous activity or exercise that involves valsalva-like maneuvres.
Exclude certain types of exercise. For example, patients who have developed peripheral neuropathy will have lost their protective sensation and should perform non-weight bearing exercises such as swimming, biking, rowing, chair and arm exercises and be discouraged from using the treadmill, taking prolonged walks, jogging or doing step exercises. Co-morbid degenerative joint disease may also be exacerbated by weight-bearing exercise.
The Physician Factor
Although most primary care physicians and endocrinologists treating diabetic patients have generally little to no training or education in exercise prescription, more and more are realizing the importance of recommending exercise to support patients in making lifestyle changes that help prevent or treat diabetes.
Exercise professionals trained to provide effective exercise prescription can work with clients’ physicians to create the supportive team they require to become more physically active.
Enlist the 4 Ms from your clients’ physicians:
- Motivation: Your client’s physician can be a key player in helping you to motivate your clients to start lifestyle changes. He or she can by promote regular exercise as a key component of therapy and identify resources in the community such as OHIP-covered diabetes education and cardiac rehabilitation programs.
- Monitoring: The physician can monitor blood work and the effect of medications and/or lifestyle changes on the client’s health.
- Medication: The physician can adjust medications appropriately as the patient loses or perhaps, in cases of non-compliance, gains weight.
- Maintenance: Patients generally trust their physicians. The physician can play an important role in helping exercise professionals encourage their clients in life long maintenance by showing a regular interest in their progress and keeping them accountable for their lifestyle choices.
Dr. Neda Amani works in Toronto and Ottawa as a family physician and is creator of The Real You Exercise Prescription program. She is the in-house doctor and health expert for Women Moving Forward, the champion physician for Active Living for Ontario and a regular speaker and presenter. You can reach her at firstname.lastname@example.org.