Being overweight and sedentary are risk factors for type 2 diabetes, a metabolic disease that, despite being preventable, affects more than 400 million adults worldwide, and causes some 5 million deaths per year. Diet and exercise are essential both for its prevention and its treatment.
A new study, the result of a collaboration of investigators from Brigham and Women’s Hospital and the Joslin Diabetes Center, used data from the Look AHEAD (Action for Health in Diabetes) study, a randomized controlled trial comparing an intensive lifestyle intervention. in patients diagnosed with type 2 diabetes and overweight or obese to track the development of cardiovascular disease over time.
In the current study, the research team tested whether physical activity at certain times of the day was associated with a greater improvement in blood glucose control. The findings suggest that patients with type 2 diabetes who were physically active in the afternoon had the greatest improvements after one year in the trial. The results of the team are published in ‘Diabetes Care’.
“In this study, we showed that adults with type 2 diabetes had the greatest improvement in glucose control when they were most active in the afternoon. We knew that physical activity is beneficial, but what our study adds is a new understanding that the timing of activity may also be important,” says Jingyi Qian, MD, of the Division of Circadian and Sleep Disorders at Brigham and study co-author.
Doctors recommend that patients with type 2 diabetes engage in regular physical activity as a method to control your blood glucose levelssince if these are elevated they can put patients at risk of heart disease, vision problems and kidney disease.
The team analyzed physical activity data from the first and fourth years of the Look AHEAD study, which included data from more than 2,400 people. During the study, participants wore a waist accelerometry recording device to measure physical activity. When the Brigham and Joslin team reviewed the data from Year 1, they determined that those who engaged in moderate to vigorous physical activity in the afternoon they had the greatest reduction in blood glucose levels. When comparing year 4 data, the afternoon group maintained a reduction in blood glucose levels. In addition, they were also most likely to stop taking their glucose-lowering medications.
The Brigham and Joslin team note that their research has limitations, such as that their study is observational and does not measure confounding factors such as sleep and dietary intake.
In future studies, the team can test their findings experimentally to investigate the underlying mechanisms that explain why the time of day of activity may influence blood glucose control. From this, the team could provide specific physical activity recommendations for the patients.
“Time seems to matter. In the future, we may have more data and experimental evidence for patients to make more personalized recommendations,” concludes Roeland Middelbeek, Assistant Researcher at Joslin Diabetes Center and co-author of the research.