By Gabe Mirkin, M.D.
Up to 70 percent of North American adults will develop diabetes or pre-diabetes, usually from insulin resistance caused by excess fat in the liver and muscles. Exercise helps to empty fat from the liver and muscles, so exercise helps both to prevent and to treat diabetes. A study of 6,718 diabetics, average age 58, followed from 4-96 weeks, found that exercise reduced HBA1c (a blood test that measures cell damage from high blood sugar levels). The more a diabetic exercised, the greater the reduction in HBA1c (Diabetes Care, Jan 2024;47:295–303). The highest level of protection from diabetic cell damage was gained with an average of 244 minutes per week of moderate-intensity aerobic exercise or 157 per week of vigorous exercise (Diabetes Care, 2024;47:196–198).
The American Diabetes Association and the World Health Organization recommend 150 to 300 minutes of moderate exercise or 75–150 minutes of vigorous exercise per week plus strength/resistance training two or more times per week. Many other studies also show that exercise is a major treatment to help prevent the horrible cell damage caused by diabetes.
Definition of Insulin Resistance
Insulin drives sugar, fat and protein from the bloodstream into cells. Insulin resistance means that the cells do not respond to insulin, so sugar accumulates in the bloodstream. Everyone’s blood sugar rises after they eat, and if blood sugar rises too high, sugar irreversibly sticks to cells and can destroy every kind of cell in your body.
To prevent blood sugar from rising too high, your pancreas releases insulin into your bloodstream, which lowers blood sugar by driving sugar from the bloodstream into the liver. However, if the liver is full of fat, it does not accept the sugar and blood sugar levels rise even higher. Insulin resistance can be reversed by emptying fat from the liver, muscles and fat cells. The larger your muscles, the less likely you are to become insulin resistant. High blood sugar causes loss of muscle size (JCI Insight, February 21, 2019;4(4)).
My Recommendations
Almost everyone will benefit from a regular exercise program. By the time people are diagnosed with diabetes, they may have already developed complications such as heart-and-lung blood vessel disease, nerve damage, or kidney and eye diseases (Nat Rev Endocrinol, 2018;14:88–98). Preventing high rises in blood sugar is crucial for lowering these risks.
Most cases of diabetes are caused by insulin resistance which usually comes from excess fat in the liver, muscles and fat cells. Both aerobic and resistance exercise help to prevent and treat diabetes by helping to empty the liver and muscles of excess sugar. Exercise also helps to reduce excess weight, high blood pressure, high LDL cholesterol, and high triglycerides, and helps to increase healthy HDL cholesterol and to strengthen muscles and bones.
Gabe Mirkin, M.D., is a sports medicine doctor and fitness guru. A practicing physician for more than 50 years and a radio talk show host for 25 years, Dr. Mirkin has run more than 40 marathons and is now a serious tandem bike rider with his wife, Diana. His website is http://drmirkin.com/. Click to read Gabe’s full bio.
This article addresses Type 2 diabetes without saying so directly. It would be helpful to make this explicit. I am a Type 1 diabetic, and exercise also helps me manage my diabetes, but in different ways. Expanding this article to include Type 1 diabetes would improve it.