DOCTOR'S VIEW ARCHIVE
Exercise Therapy in Type 2 Diabetes: Part 1 - The Benefits
Medical Editor: William C. Shiel, Jr., MD, FACP, FACR
A 52 year old woman came into my office last week with recently diagnosed diabetes. She works as an administrative assistant and admitted to having a rather non-active lifestyle. We discussed medications and basic nutritional changes. We also talked about the importance of exercise in patients with diabetes.
Physical exercise is important for all of us. Physical conditioning is one of the most important quality of life factors that we can actually improve, thus contributing to a longer and healthier life. Even better, exercise is empowering since each person can control the amount of activity they do to achieve the maximum benefit.
Exercise presents a special challenge in patients with type 1 diabetes, and I will address this topic in another article. In this discussion, I will focus on exercise in type 2 diabetes.
What are the benefits of exercise in people with type 2 diabetes?
For the person with type 2 diabetes, or the high-risk individual who is trying to prevent the development of diabetes, there is an enormous body of research literature documenting the benefits of exercise. Unfortunately, there is little data on how to motivate patients to maintain a long term healthy regimen.
A major benefit of exercise is its effect on the heart and the associated reduction in death from heart disease. In addition to lowering the risk of heart disease in type 2 diabetes, exercise helps to decrease the chances of developing diabetes. This can be especially important for those with borderline diabetes. In one study, the risk of developing diabetes was reduced by 24% (based on an energy expenditure of 2000 calories per week through exercise). This protective effect of exercise was seen the most in the group at highest risk for developing type 2 diabetes. The mechanism for this benefit is that exercising muscles are more sensitive to circulating insulin. They thus take up blood sugar more easily and use sugar more effectively. Research has shown that even short term aerobic exercise improves the sensitivity of muscles to insulin.
There is a strong association between diabetes and the location of fat in the body. It has been known for a long time that people with increased internal belly fat (the classic apple-shaped person with a round belly versus the pear-shaped person with a heavier deposit of fat around the hips and thighs) have a higher risk for insulin resistance, high cholesterol, and high blood pressure. This triad of diseases is part of a disorder called " Syndrome X." Interestingly, in some patients who are not overweight by definition, internal belly fat may still be high, as visualized with special imaging tests of the abdomen.
For example, a classic apple-shaped obese person is a Sumo wrestler. However, Sumo wrestlers are physically active and actually have low internal belly fat stores. Therefore, they are rarely afflicted with blood sugar or cholesterol problems!
In addition to its benefits on muscle insulin sensitivity, aerobic exercise also improves blood cholesterol levels and blood pressure control. This benefit occurs regardless of weight loss. In one study, patients with type 2 diabetes on a 3 month exercise program reduced their triglyceride levels by 20%, increased their good cholesterol (HDL) by 23%, and decreased their blood pressure to better levels too!
The benefits of exercise in patients with diabetes, and in those at high-risk for developing type 2 diabetes (and those with Syndrome X), may include the following:
"Wow - exercise sounds like an important part of managing diabetes!" In general, it is. BUT, like everything else, it's not quite black and white. In certain situations, patients with diabetes should approach any exercise regimen with caution. Additionally, exercise may need to be avoided, at least temporarily, in some patients.
In Part 2 of this discussion, I will focus on specific concerns about exercise in type 2 diabetes and any problems that might arise. I will also address what you and your doctor should discuss before starting an exercise program.
For those of you who are inspired by the data presented in this article, I encourage
you to make healthy lifestyle changes. Discuss your goals with your doctor first to be sure your
plan is safe and reasonable.
Last Editorial Review: 4/5/2002