Diabetes is a disorder that is characterized by high levels of blood sugar which occurs due to changes in insulin production, insulin sensitivity, or both. This long term elevation in blood sugar levels has serious health effects. Specifically, long term elevations of blood sugar can damage small blood vessels. This damage may then affect vision, kidney and nerve function, bone health, and lead to increased risk of heart attack and stroke, etc.
The prevalence of diabetes is increasing worldwide. In 1985 it was estimated that 30 million people were diagnosed with the disease. Last year, the number of people diagnosed with diabetes was estimated at 371 million people, more than a tenfold increase. This trend for increasing rates of diagnosis is even greater in Canada, where it is estimated that the number of Canadians diagnosed between 1998 and 2009 increased by 230%. It is currently estimated that 2.4 million Canadians have diabetes, and that the incidence will continue to grow1.
One of the most important ways to manage diabetes is through physical activity. It is currently recommended that people with diabetes participate in both regular aerobic and resistance exercise. The participation in these forms of exercise has been shown to be effective in improving blood sugar regulation, reducing insulin resistance, substantially lowering the mortality risk in people with diabetes, and decreasing the risk of several other diabetes related complications (bone and muscle loss, foot ulcers, nerve damage, etc).
Insulin, Blood Sugar Regulation, and the Effects of Exercise
Insulin is a hormone produced in the pancreas that regulates carbohydrate (sugar) and fat metabolism in the body. When eating a meal, insulin is release from the pancreas, entering into the blood stream where it stimulates cells of the body (liver, muscles, fat cells) to take up sugar that was absorbed from food. The cells of the body then use sugar for energy or store it for future use.
In diabetes, the control of blood sugar is impaired. In type 1 diabetes, the cells of the pancreas that produce insulin are destroyed and insulin is not produced. This lack of insulin impairs body tissues to take up sugar. Furthermore, blood sugar levels cannot be properly regulated, remaining elevated. In type 2 diabetes, cells of the body become resistant to the effects of insulin, again leading to elevated levels of blood sugar. Moreover, as type 2 diabetes progresses, the pancreas can lose the ability to produce enough insulin, so there may be both a lack of insulin in addition to the loss of insulin sensitivity.
Exercise has been shown to be very effective in helping regulate blood sugar levels and improving the long term health of diabetics. Exercise has been shown to be effective in regulating blood sugar levels by stimulating active muscles to take up blood sugar without the need for insulin, effectively lowering blood sugar for at least 24 hours following exercise2. In addition to the non-insulin mediated absorption of sugar, exercise has been shown to lower the insulin resistance found in type 2 diabetes1.
To achieve blood sugar regulation benefits, people with diabetes should take part in both aerobic and resistance exercise. A minimum of 30 minutes per day for 5 days of the week should be allotted for aerobic exercise (e.g. brisk walking, swimming, jogging, bicycling, aerobics, dancing, etc) and at least two sessions per week of resistance exercise (weights and other forms of strength training) is recommended1.
Safety considerations with exercise and diabetes
For the majority of individuals with diabetes, participation at a moderate level (i.e. brisk walking) of physical activity is safe. However, individuals with certain pre-existing health concerns (autonomic or peripheral neuropathy, unstable angina, vision problems, or with presence of foot/leg ulcers), should speak to a health professional for further evaluation prior to starting a new exercise plan.
It is important to be aware that resistance training and vigorous aerobic activity (i.e. aerobics, jogging, brisk walking up an incline, etc.) can lead to an unsafe level of blood sugar in diabetics both during and post exercise. For example, vigorous exercise can cause low blood sugar (hypoglycemia) in diabetics who are on insulin or insulin secreting medications1-2. Thus it is important to first speak to a health care professional about how to safely monitor and regulate blood sugar before, during and after exercise.
Exercise is an essential component for the prevention and management of diabetes. It can help to regulate blood sugar levels, reduce risk of cardiovascular disease, and can reduce the risk of complications associated with diabetes.
If you have diabetes, or if you are at risk of developing diabetes, it is important that you ensure that your blood glucose levels are monitored and properly controlled. Diabetes treatment and blood glucose control should include a personalized diet and exercise plan that is tailored to one’s specific situation. In practice I help patients who are at risk of developing diabetes, or who have diabetes, to improve their blood sugar control through diet and exercise. If you have questions about diabetes, exercise, how to exercise safely with diabetes, or how Naturopathic Medicine can help you, please call 613-290-6115.
Graham Beaton is a Naturopathic Doctor practicing in Ottawa at the Ottawa Collaborative Care Centres.
1. Sigal, R.J. et al. Physical Activity and Diabetes – Canadian Diabetes Association Clinical Practice Guidelines Expert Committee. Can J Diabetes 37;2013:S40-44.
2. 2. Colberg, S. R. et al. Exercise and Type 2 Diabetes: the American College of Sports Medicine and the American Diabetes Association join position statement. Diabetes Care 2010;33(12):e147-e167.
