Physical Activity Helps Prevent Diabetes Independent of Weight Loss

The benefits of exercise in diabetes prevention go beyond weight loss.

A recent study presented at the American Diabetes Association’s (ADA) annual conference followed up with a subgroup of participants from the Diabetes Prevention Program (DPP) multicenter study, which was published in 2002.

The researchers observed that moderate increases in regular physical activity seemed to help protect overweight participants with prediabetes from progressing to type 2 diabetes (T2D).

The health benefit of exercise was strongest for prediabetic individuals who were the most inactive at baseline (reporting less than 150 minutes of activity per week). Those who increased their level of activity to 150 minutes or more per week experienced a 5% lower incidence of diabetes.

Notably, this effect was seen even after controlling for weight loss and other covariates.

“Until now, the importance of physical activity in preventing diabetes development in the [DPP] was thought to be due to its role in achieving weight loss and weight maintenance; however, it was not considered a strong key factor alone,” stated Andrea Kriska, PhD, professor of epidemiology at the University of Pittsburg, at the ADA meeting.

In the initial DPP investigation, participants were randomized into 3 intervention cohorts: lifestyle intervention, metformin, or placebo. Then, they were followed for 3 years.

The results, which were published 14 years ago, showed that healthy lifestyle modifications, including weight loss and increased physical activity, reduced the risk of T2D by 58% over 3 years for overweight patients with prediabetes.

Lifestyle intervention was found to be the most effective preventive measure against T2D—even besting the metformin cohort. Researchers asked participants to participate in a DPP Outcomes Study to further explore the effect of lifestyle intervention on T2D prevalence.

The subgroup of 1793 participants was divided into 3 cohorts: 589 were prescribed lifestyle changes only, 599 were prescribed metformin, and 605 were prescribed placebo. Each participant wore an activity monitor for 1 week, and an interviewer-administered Modifiable Activity Questionnaire tracked physical activity annually.

Diabetes statuses were monitored by yearly tests for glucose tolerance and semi-annual fasting blood glucose tests. Their progress was followed for an average of 12 years.

Across all intervention cohorts, the participants who were the most physically active saw the lowest incidence of diabetes, regardless of weight loss. The protective effect of exercise was small yet significant, yielding a 2% lower incidence of T2D across the total study population for every increase of 6 metabolic equivalents, or 1.5 hours of brisk walking, per week.

Although weight loss remains an important factor that definitely reduces T2D risk, clinicians should remind prediabetic patients that exercise can improve their health, regardless of the number they see on the scale.

“It is important for health care professionals to look beyond their high-risk patients’ weight, and also consider their physical activity levels, when discussing strategies to prevent progression to [T2D],” Dr. Kriska advised during a press conference at ADA. “Maintaining your patients’ adequate physical activity levels is very important in diabetes progression, regardless of any weight changes. Both physical activity and weight intervention need to be encouraged and supported.”