Aerobic Exercise Programs May Help Prevent Diabetes in Individuals with Obesity

The risk of diabetes was reduced by approximately 50% in both the vigorous and moderate aerobic exercise groups compared with the nonexercise group.

A 12-month vigorous or moderate aerobic exercise program could generate long-term benefit on type 2 diabetes (T2D) prevention in patients with central obesity, according to 10-year follow-up of a randomized clinical trial.

Similar trials have reported beneficial results of lifestyle intervention for the prevention of diabetes, but these trials combined exercise with diet and included individual or group consulting. In contrast, the current trial performed strict coaching in the exercise programs during the 1-year intervention and all participants were instructed not to change their diet.

“Regarding the importance of obesity management in the prevention of T2D addressed by the latest American Diabetes Association guideline, our results are supportive of physical exercise as an effective scheme for obesity management to delay the progression of T2D, and vigorous and moderate aerobic exercise programs could be implemented for prevention of T2D in people with obesity,” wrote corresponding author Xiaoying Li, MD, PhD, Ministry of Education Key Laboratory of Metabolism and Molecular Medicine, Department of Endocrinology and Metabolism, Zhongshan Hospital, Fudan University.

Lifestyle interventions including diet and exercise play a key role in the prevention of T2D in at-risk individuals, but the isolated effects of vigorous and moderate exercise are uncertain. Li and colleagues performed a 10-year follow-up study based on their previous RCT to assess long-term effects of exercise on the prevention of diabetes between July 2021 and May 2022.

The trial consisted of vigorous aerobic exercise (n = 73), moderate aerobic exercise (n = 73), and nonexercise control groups (n = 74) in individuals with central obesity and nonalcoholic fatty liver disease. At the end of the 12-month intervention, all participants were encouraged to continue with a healthy lifestyle and moderate intensity aerobic exercise.

They were then followed up with at 2-year and 10-year visits to assess the incidence of T2D and the changes in body weight, waist circumference, and metabolic risk factors. The study defined incident diabetes as fasting plasma glucose of 126 mg/dL or greater, hemoglobin A1c (HbA1c) levels of 6.5% or greater, and/or the use of antidiabetic medication.

From 220 eligible participants in the original RCT, 208 (94.5%) participants finished the 1-year exercise intervention. At the 2-year and 10-year follow-up visits, 195 (88.6%) and 179 participants (81.4%) continued with the assessment of incident diabetes, respectively.

Similar metabolic equivalents of leisure time physical activity among the 3 groups were observed at baseline but were found higher in moderate and vigorous exercise groups than in the nonexercise group at the end of 1-year intervention. No significant differences were reported among the 3 groups at the 10-year follow-up, but there was a trend of higher levels of leisure time physical activity in the exercise group than the nonexercise group.

In the 10-year follow-up, data show the cumulative incidence of T2D was 2.1 per 100 person-years (PYs) in the vigorous group, compared to 1.9 per 100 PYs in the moderate group, and 4.1 per 100 PYs in the nonexercise groups.

The risk of diabetes was reduced by 49% in the vigorous aerobic exercise group and by 53% in the moderate aerobic exercise group compared with the non-exercise group. Investigators reported similar results of moderate and vigorous aerobic exercise in those who completed 12-month interventions.

Further results show HbA1c and waist circumference to be significantly reduced in the vigorous and moderate exercise groups compared with the nonexercise group. Meanwhile, fasting plasma glucose levels and weight regain were lower in the exercise groups, although significant differences were not detected.

The research letter, “Effect of Moderate and Vigorous Aerobic Exercise on Incident Diabetes in Adults with Obesity: A 10-Year Follow-up of a Randomized Clinical Trial,” was published in JAMA Internal Medicine.