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Thursday, May 23, 2013
Staying physically active is important for everyone, especially for people with diabetes. Many studies have shown beneficial effects of exercise on blood sugar control, heart health and sense of well-being. This article addresses both how diabetes affects your ability to be physically active and how physical activity or exercise can affect someone with diabetes.
The basic problem in diabetes is that fuels, especially carbohydrates (like sugar and starch), but also protein and fat, don't get distributed to the tissues they usually go to (for example, to the muscle, brain, liver and fat tissue) in the necessary manner and build up in the blood and outside of the cells in a person's body. Vigorous physical activity generally involves increased muscle activity and an increased need for fuel in the muscle. Changes in fuel distribution because of diabetes and alterations in fuel distribution from exercise going on at the same time can have opposite effects.
Exercise generally tends to lower the blood sugar, but there are situations in which it can cause it to rise especially in individuals with poorly controlled blood sugar. Changes in diabetes medications and food intake are frequently needed to prevent dangerous consequences and it is best when those are planned for in advance. If your physical activity, your medicine, and your diet are not coordinated, this can put you at risk for either very low blood sugar (hypoglycemia) or very high blood sugar (hyperglycemia). There are also some differences in how it affects people with type 1 diabetes versus those with type 2.
Type 1 diabetes is the form in which all the cells which produce insulin have been destroyed. People with type 1 diabetes require insulin treatment. Once insulin is taken, it directs fuel to its target tissues, regardless of the demands of the exercise. There are mechanisms in the body, such as hormones, to prevent the blood sugar from going too low when the muscle demands more fuel during and after exercise. These mechanisms can prevent low blood sugar in this situation, but only up to a point. There are warning signs of hypoglycemia, which prompt people to eat something to prevent things from getting out of hand. Some common warning signs of hypoglycemia include:
However, in some people with type 1 diabetes, those hormones that protect against low blood sugar don't work properly. Those people need to be more on the lookout for lows and perhaps compromise on how "tightly" they control their blood sugar. Planning means timing exercise in relation to medicines and meals, sometimes reducing medicine or increasing food, or both.
Type 2 diabetes is due to a combination of effects including:
Exercise markedly improves the body's response to insulin in the blood sugar and that is key to achieving excellent blood sugar control using the smallest amount of medicine possible. Physical limitations or injuries can make finding a practical form of exercise a challenge, but the payoff is great in terms of improved blood sugar control and a sense of well-being and reduced risk of heart disease.
There are dramatic benefits of exercise for people with diabetes. However, it is important to understand how your particular medicines and diet will affect your response to exercise and plan accordingly. That is an important benefit of receiving care for diabetes by a team approach with a physician,a teaching nurse, and a dietician.
The American Heart Association and The American Diabetes Association recommend at least 150 minutes of moderate-intensity aerobic activity or at least 90 minutes of vigorous aerobic exercise per week. The activity should be distributed over at least three days each week, with no more than 2 consecutive days of inactivity. A larger amount of exercise (seven hours per week) may be beneficial for maintaining weight loss in the long run. If you have been inactive, it may be important for you to check with your health care professional to decide whether heart function testing is necessary before starting out on a program of more vigorous exercise.
This article is a NetWellness exclusive.
Last Reviewed: Jun 05, 2008
Robert M Cohen, MD
Professor of Clinical Medicine
College of Medicine
University of Cincinnati
Jenny Tong, MD
College of Medicine
University of Cincinnati