Exercise is often recommended to diabetes patients looking to improve their blood sugar, insulin sensitivity, blood pressure, and cholesterol levels. Some doctors even call it a prescription for diabetes management. Although experts have agreed that physical activity is beneficial for controlling diabetes, research has not been so definitive when it came to preventing the condition. Until now.

Researchers led by Dr. Lisa Chow from the University of Minnesota have concluded a study analyzing over 20 years of research on exercise levels and risk for diabetes development. Their findings show that people with higher levels of physical fitness tend to have a lower risk for being diagnosed with either diabetes or prediabetes.

"This study is clinically relevant as it provides evidence to support commonly accepted dogma that fitness is beneficial in reducing the risk for prediabetes/diabetes,” said the authors of the study in a statement. “As this benefit remained significant even when adjusting for BMI, exercise programs remain critically important for reducing the development of prediabetes and diabetes."

Chow and her colleagues gathered data using the Coronary Artery Risk Development in Young Adults study, or CARDIA, which has investigated the link between exercise and the development of diabetes or prediabetes for over 20 years. A total of 4,373 black and white women and men from Birmingham, Ala.; Chicago, Ill.; Minneapolis, Minn.; and Oakland, Calif., were enrolled between 1985 and 1986.

Each participant had their exercise levels tested through treadmill exercise at the first, seventh, and 20th years of the study. It’s important to note that CARDIA focused on levels of cardiovascular fitness, which is elevating the heart rate to improve the body’s consumption of oxygen. Higher cardiovascular levels are influenced by both genetic factors and exercise.

Researchers assessed diabetes and prediabetes development around every five years and found a lower risk among participants with higher fitness levels. Using another study, they found that achieving the level of fitness needed to ward off diabetes and prediabetes required 30 minutes of vigorous physical activity a day, five days a week, or 40 minutes of moderate physical activity a day, five days a week.

High-intensity interval training, which has garnered quite a bit of attention around the fitness world, has also made waves among experts who say it can be used to protect the health of patients with diabetes. Researchers from the University of Western Ontario in Canada compared different markers of health in diabetes patients who exercised using high-intensity interval training and those who used traditional low-intensity training 30 minutes a day, five days a week.

Not only did the high-intensity workout improve the cholesterol levels, blood sugar, and weight of Type 2 diabetes patients, it also improved their cardiovascular health, according to stress tests. Short bursts of exercise improve heart health by changing its structure and function, especially in the left ventricle which is essential to blood flow.

Source: Bosch T, Odegaard A, Chow L, et al. Twenty Year Fitness Trends in Young Adults and Incidence of Prediabetes and Diabetes: the CARDIA Study. Diabetologia . 2016.