Also known as borderline diabetes, prediabetes is when your before-meal blood sugar is between 100 and 125 mg/dl (the normal range is 70 to 99 mg/dl). The threshold for diabetes is 126 mg/dl or higher. Many people with prediabetes can develop type 2 diabetes.
Having diabetes markedly increases the risk for developing large blood vessel diseases, such as heart and peripheral artery disease, and small blood vessel diseases that affect body organs such as the eyes and kidneys. However, all is not grim for people with prediabetes.
Without exercise, muscles are less able to respond to insulin, a body chemical produced by the pancreas, which is needed to process glucose, a form of sugar that is a major source of energy for the muscles. This is known as insulin resistance and being overweight or obese and physically inactive can make it worse. With this condition, blood sugar levels increase and, after they get to a certain level, you have prediabetes. As insulin resistance worsens, you can develop diabetes, as the amount of insulin produced cannot keep up.
The good news is that regular exercise reduces blood sugar buildup by reducing insulin resistance. Weight loss and proper nutrition reduces the amount of carbohydrates (sugars) in the body and, as a result, the body also starts to burn more of the stored fat, which reduces the risk of prediabetes progressing to diabetes.
Along with a healthy body weight, exercise is one of the best ways to prevent or reverse insulin resistance and thereby reverse prediabetes. Exercise must be done regularly if it is to be helpful. Although a single walk or bike ride lowers blood sugar, the benefit does not last long. Therefore, you need to exercise several times a week to keep the muscles in shape and the blood sugar in check. The science is irrefutable: even small amounts of exercise can cut the risk of developing diabetes.
In a large research study—known as the Diabetes Prevention Program—in which Johns Hopkins researchers participated (including the author of this article), the risk of developing diabetes was reduced by 58% in participants with prediabetes who made lifestyle changes. In comparison, people who received a medicine for blood sugar control but did not make any lifestyle changes only reduced their risk by 34 percent.
A lifestyle program for diabetes prevention consists of three major components:
These lifestyle changes maintain good health by lowering blood pressure and triglycerides (another blood fat), increasing HDL cholesterol (the good kind) and keeping off the extra pounds.
Another very important benefit of exercise, independent of weight loss, is that it seems to target the extra weight around and above the abdomen, usually referred to as central, abdominal or belly fat. Our exercise and weight loss studies at Johns Hopkins have shown that belly fat can be lost even if not fully reflected in a loss of total body weight on the scale. The result is a reduction in blood sugar levels resulting from reduced insulin resistance.
Content courtesy of Kerry Stewart, Ed.D., professor of medicine and director of clinical and research exercise physiology at the Johns Hopkins University School of Medicine. The content was reproduced with permission of the office of Marketing and Communications for Johns Hopkins Medicine International. Additional reuse and reprinting is not allowed. The information aims to educate readers and is not a substitute for consultation with a physician.