Reducing sedentary behavior lowers risk of diabetes and heart disease in patients with metabolic syndrome

Within 3 months, reducing daily sedentary time helps lower the risk of type 2 diabetes and cardiovascular diseases in persons with metabolic syndrome. 

Researchers reported the findings on May 2, 2022 in the Journal of Science and Medicine in Sport.

“It is an encouraging thought that health benefits can be achieved by reducing the time spent sitting and increasing the amount of even light-intensity physical activity. For many, this may be an easier starting point than increasing actual exercise,” said investigator and Ph.D candidate Taru Garthwaite from the University of Turku in Finland.

As background, the authors noted that Type 2 diabetes and cardiovascular diseases are the most common chronic diseases in the world, and risk for both increases with obesity caused by physical inactivity and unhealthy diet.

They added that while regular exercise helps in weight management and, therefore, disease prevention, many adults do not exercise effectively and most spend their days sitting.

The goal of the study was to determine whether health benefits appear in three months with a reduction in daily sedentary time.

The investigators enrolled and randomized sedentary middle-aged adults with metabolic syndrome into intervention (n = 33) and control (n = 31) groups.

They instructed the intervention group subjects to increase movement and light physical activity by 1 hour/day. They instructed control group subjects to continue in their pre-enrollment and sedentary habits.

For three months, the researchers measured sedentary behavior, breaks in sedentary behavior, standing, and physical activity using hip-worn accelerometers.

“What makes our research design unique is that sedentary time and physical activity of both groups were measured with accelerometers throughout the entire three-month period, whereas in earlier studies activity has typically been measured only for a few days at the beginning and end of the study period. This makes it possible to receive more information on the actual behaviour changes over a longer time period,” said Garthwaite.

The investigators also performed fasting blood sampling and measurements of anthropometrics, body composition, and blood pressure at baseline and at three months.

They reported that, within 3 months, the intervention group reduced sedentary behavior by 50 min/day through an increase light-intensity and moderate-to-vigorous physical activity.

Control group subjects maintained their baseline activity levels.

At three months, the researchers found health effects favoring the intervention group — in fasting insulin (intervention group: 83.4 vs. control group: 102.0 picomoles per liter [pmol/l)], insulin resistance (HOMA/Homeostatic Model Assessment for Insulin Resistance, 3.2 vs. 4.0 respectively), HbA_1c 37 vs. 38 millimoles per mole [mmol/mol] respectively), and liver enzyme alanine aminotransferase (28 vs. 33 international units per liter) respectively.

“It is an encouraging thought that health benefits can be achieved by reducing the time spent sitting and increasing the amount of even light-intensity physical activity. For many, this may be an easier starting point than increasing actual exercise,” said Garthwaite. “Reducing the time spent sitting might still slow down the development of these diseases, but greater benefits can of course be gained by increasing the amount or intensity of physical activity in addition to sitting less,” she added.

The authors concluded, “Reducing sedentary behavior by 50 min/day and increasing light-intensity and moderate-to-vigorous activity showed benefits in several cardiometabolic biomarkers in adults with metabolic syndrome. Replacing some of the daily sedentary behavior with light-intensity and moderate-to-vigorous physical activity may help in cardiometabolic disease prevention in risk populations.”