Benefits of HIIT in people with type 2 diabetes

This study investigated whether a combination of high-intensity interval training (HIIT) exercise plus post-exercise protein could reduce the risk of cardiovascular disease in people with type 2 diabetes (T2D). It was determined that HIIT reduced the stiffness and thickness of arterial walls and reduced the resting heart rate. However, receiving post-exercise protein was not found to have an effect.

People with T2D are at increased risk of developing cardiovascular disease. Increased arterial stiffness, increased arterial wall thickness, and increased resting heart rate are features of cardiovascular disease.

Lifestyle changes, including diet and exercise, are the main methods used to reduce cardiovascular disease risk in people with T2D. Recent evidence suggests that HIIT is effective in people with T2D. During HIIT a person switches between intervals of intense activity and short intervals of rest/recovery. Whether the combination of HIIT and post-exercise protein supplementation has greater benefits is uncertain. Furthermore, the effects of HIIT on arterial stiffness and arterial wall thickness are not known.

53 adults with T2D were recruited for this study. None of the participants had been diagnosed with cardiovascular disease. They were divided into 3 groups. All groups participated in 3 sessions of HIIT per week for 12 weeks. After exercise, one group received skim milk. Another group received a drink containing the same types and amount of protein as milk. The last group received a water-based placebo (substance with no active effect) drink that contained no protein. The participants were examined before and 48-72 hours after the last training session.

Two participants did not complete the trial. One stopped due to personal reasons. The other participant had a non-fatal heart attack during the 8th week of training.

After 12 weeks the thickness of the femoral artery decreased by 0.03 mm. The femoral artery is the main artery in the thigh. It is very susceptible to the development of vascular disease. After 12 weeks arterial stiffness was also found to decrease. The average resting heart rate decreased from 70.4 beats per minute to 67.8 beats per minute. There was no difference between the 3 post-HIIT drink groups after 12 weeks. 

The study concluded that regular HIIT training reduces arterial stiffness, arterial wall thickness, and resting heart rate in adults with T2D. The addition of post-exercise protein did not provide additional benefits.

This study only examined a small number of participants. Thus the results may not apply equally to all people with T2D.

Discuss the benefits of HIIT and other exercise programs with your physician. It is always important to check with your physician before starting a new exercise program or increasing the intensity of a previous program.