Diabetic Heart Benefits of Exercise

Two new studies show that high-intensity exercise can significantly improve cardiometabolic risk factors when compared with a traditional sustained-exercise program and also can improve cardiac structure and function in patients with type 2 diabetes mellitus (T2DM).

Clinicians generally prescribe low-intensity, sustained exercise as part of diabetes rehabilitation. Recently, studies have demonstrated short-term cardiometabolic benefits of high-intensity, burst exercise in healthy volunteers.

Study 1

Researchers led by senior author Dr. Paul Poirier of the Université Laval in Quebec City, Canada, conducted a study to examine the impacts of burst exercise in 76 newly diagnosed diabetics. The patients had an average age of 65 years, an average body mass index (BMI) of 31 kg/m², and average hemoglobin A1C (HbA1c) of 8.2%.

The patients were randomized into a control group who performed routine sustained exercise for 30 minutes at 60% of target heart rate and an intervention group who performed high-intensity burst exercises, 3 periods of 10 minutes at 85% of target heart rate. All patients underwent routine blood tests and stress tests and logged their exercise duration.

After 3 months, those patients prescribed the burst regimen exercised, on average, 27% more than the control group. Burst exercise patients showed a 2.3 fold greater improvement in HbA1c and small, but statistically significant, improvements in low-density lipoprotein and high-density lipoprotein cholesterol levels, as well as more improvements in trigylcerides, BMI, and cardiopulmonary fitness compared to controls.

These improvements held up even among patients who exercised similar number of minutes per day.

In conclusion, the researchers stated: “Burst exercise appeared to significantly improve the cardiometabolic status of newly diagnosed diabetic patients. This regimen may represent a simple and effective way to improve diabetes rehabilitation.”

Study 2

Heart disease is the leading cause of death among T2DM patients, yet few strategies target cardiac dysfunction in diabetes. These researchers, led by Sophie Cassidy of the University of Newcastle, United Kingdom, conducted a randomized controlled trial to investigate high-intensity intermittent training as a potential therapy to improve cardiac structure and function in T2DM.

The 23 patients with T2DM were randomized to 12 weeks of high-intensity intermittent training (12 patients) or standard care (11 patients). The exercise regimen consisted of 3 sessions per week of stationary cycling at a local gym. The high-intensity group started with initial intervals of 2 minutes, with 3-minute recovery periods, increasing in 10-second increments each week, to reach 3 minutes 50 seconds by the end of 3 months. Patients also completed an exercise diary.

Compared with controls, high-intensity intermittent training improved cardiac structure and systolic function. Early diastolic filling rates increased and peak torsion decreased.

In addition, there was a 39% relative reduction in liver fat and a modest, but significant, reduction in HbA1c from 7.1% to 6.8% in the treatment group.

The researchers noted that this is the first study to demonstrate improvements in cardiac structure and function to be recorded following an exercise intervention in T2DM.

They suggested that clinicians consider high-intensity intermittent training as a therapy to improve cardiometabolic risk in patients with T2DM.