In an analysis of the Look AHEAD study, researchers found that participants who were physically active in the afternoon had greater reductions in blood sugar than those who were most active at other times of day
BOSTON – Over 37 million Americans have diabetes, and 90-95% of that population are diagnosed with type 2 diabetes. Lifestyle interventions, such as a healthy diet and a regular physical activity program, are methods to manage diabetes. A new study from a collaboration of investigators at Joslin Diabetes Center and Brigham and Women’s Hospital uses data from the Look AHEAD (Action for Health in Diabetes) study, a randomized controlled trial that compared an intensive lifestyle intervention with diabetes support and education in patients diagnosed with type 2 diabetes and overweight or obesity to track the development of cardiovascular disease over time. In the current study, the research team assessed whether physical activity at certain times of day was associated with greater improvement in blood glucose control. Their findings suggest patients with type 2 diabetes who were physically active in the afternoon had the largest improvements after one year in the trial. The team’s results are published in Diabetes Care.
“In this study, we shown that adults with type 2 diabetes had the greatest improvement in glucose control when they were most active in the afternoon,” said co-corresponding author Jingyi Qian, PhD, from the Division of Sleep and Circadian Disorders at the Brigham. “We’ve known that physical activity is beneficial, but what our study adds is a new understanding that timing of activity may be important too.”
Physicians recommend that patients with diabetes participate in regular physical activity as a method to manage their blood glucose levels. Elevated blood glucose levels can put people with type 2 diabetes at risk of heart disease, vision impairment, and kidney disease.
The team analyzed physical activity data from the first and fourth years of the Look AHEAD study, which included data from over 2,400 participants. During the study, participants wore a waist accelerometry recording device to measure physical activity. When reviewing the data from year 1, they determined that those who engaged in moderate-to-vigorous physical activity in the afternoon had the greatest reduction in blood glucose levels. Upon comparing the data from year 4, the afternoon group maintained a reduction in blood glucose levels. In addition, the afternoon group also had the highest chance of stopping their glucose-lowering/diabetes medications.
The team notes that their investigation has limitations; for example, their study is observational and does not measure confounding factors like sleep and dietary intake. In future studies, they may test their findings experimentally to investigate the underlying mechanisms that may explain why time of day of activity may influence blood glucose control. From this, the team may be able to provide specific physical activity recommendations for patients.
“Timing does seem to matter,” said co-corresponding author Roeland Middelbeek, MD, assistant investigator at Joslin Diabetes Center. “Going forward, we may have more data and experimental evidence for patients to give more personalized recommendations.”
This study was funded by the National Heart, Lung, and Blood Institute (K99-HL-148500, R01-HL140574), National Institute on Aging (RF1AG059867 and RF1AG064312), and National Institute of Diabetes and Digestive and Kidney Diseases (K23-DK114550). The Look AHEAD study was supported by the Department of Health and Human Services through the following cooperative agreements from the National Institutes of Health, NIDDK: DK57136, DK57149, DK56990, DK57177, DK57171, DK57151, DK57182, DK57131, DK57002, DK57078, DK57154, DK57178, DK57219, DK57008, DK57135, and DK56992. Additional funding was provided by the National Heart, Lung, and Blood Institute, National Institute of Nursing Research, National Center on Minority Health and Health Disparities, National Institutes of Health Office of Research on Women’s Health, and the Centers for Disease Control and Prevention. This research was supported in part by the NIDDK Intramural Research Program. Additional support was received from the Johns Hopkins Medical Institutions Bayview General Clinical Research Center (M01RR02719), the Massachusetts General Hospital Mallinckrodt General Clinical Research Center and the Massachusetts Institute of Technology General Clinical Research Center (M01RR01066), the University of Colorado Health Sciences Center General Clinical Research Center (M01RR00051) and Clinical Nutrition Research Unit (P30 DK48520), the University of Tennessee at Memphis General Clinical Research Center (M01RR0021140), the University of Pittsburgh General Clinical Research Center (M01RR000056), the Clinical Translational Research Center funded by the Clinical & Translational Science Award (UL1RR024153) and National Institutes of Health NIDDK grant (DK 046204), the VA Puget Sound Health Care System Medical Research Service, Department of Veterans Affairs, and the Frederic C. Bartter General Clinical Research Center (M01RR01346). The Indian Health Service (IHS) provided personnel, medical oversight, and use of facilities.
The following organizations have committed to make major contributions to Look AHEAD: Federal Express, Health Management Resources, Johnson & Johnson, LifeScan Inc., Optifast-Novartis Nutrition, Roche Pharmaceuticals, Ross Product Division of Abbott Laboratories, SlimFast Foods Company, and Unilever. J.M.J. is on the scientific advisory board for Wondr Health, Inc. F.A.J.L.S. serves on the Sleep Research Society Board of Directors and has received consulting fees from the University of Alabama at Birmingham. R.J.W.M. has received research funding from Novo Nordisk unrelated to this work.
About Joslin Diabetes Center
Joslin Diabetes Center is world-renowned for its deep expertise in diabetes treatment and research. Part of Beth Israel Lahey Health, Joslin is dedicated to finding a cure for diabetes and ensuring that people with diabetes live long, healthy lives. We develop and disseminate innovative patient therapies and scientific discoveries throughout the world. Joslin is affiliated with Harvard Medical School and one of only 18 NIH-designated Diabetes Research Centers in the United States.
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