Reducing Sedentary Time By An Hour Per Day Can Provide Health Benefits in Metabolic Syndrome

Taru Garthwaite, MSc

Reducing sedentary time by just an hour per day among patients with metabolic syndrome could reduce improve glycemic control and other markers of cardiometabolic health, according to results from a recent trial.

A trial assessing the effects of a low-intensity intervention aimed at reducing sedentary by 1 hour per day, results of the study demonstrate reducing sedentary time and increasing light-intensity physical activity was associated with improvements in several cardiometabolic biomarkers in adults with metabolic syndrome, including fasting insulin levels, HbA1c, and liver alanine aminotransferase.

“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 lead investigator Taru Garthwaite, MSc, a doctoral candidate at the University of Turku in Finland, in a statement.

Although it is common knowledge among providers and laypersons that decreasing sedentary is associated with improved health outcomes, the magnitude of benefit is the subject of debate depending on the patient population in question. With this in mind, the current study was conducted by Garthwaite and colleagues from the Turku PET Centre and the UKK Institute in Finland to assess the impact of a low-intensity intervention aimed at limiting sedentary by an hour per day and replacing it with standing time or light-intensity physical among patients with metabolic syndrome.

A parallel-group randomized controlled trial, the study was conducted between April 2017 and November 2019, with eligible patients recruited through newspaper advertisements and leaflets distributed in the local community. investigators sought to enroll a population of sedentary and inactive working-aged adults with metabolic syndrome. Specific inclusion criteria required patients to be 40-65 years of age, have less than 120 minutes per week of self-reported moderate to vigorous physical activity, accelerometer-measured sitting time of 10 hours or more per day, a baseline BMI of 25-40 kg/m2, a blood pressure greater than 160/100 mmHg, and fulfillment of at least 3 prespecified metabolic syndrome criteria.

The aim of the intervention was to reduce sedentary behavior by 1 hour per day compared to the reported sedentary time during the baseline screening. those randomized to the intervention received guidance in the form of 1-hour tailored personal counseling sessions to sit less by increasing standing and light-intensity physical activity, without intentionally adding exercise or moderate-to-vigorous physical activity.

A total of 263 patients volunteered to participate in the trial. Of these 155 were screened and 64 were ultimately selected for inclusion. Of the 64 chosen to participate, 63 completed the trial, with 1 participant dropping out due to personal reasons. The mean age of the final study cohort was 58 (SD, 7) years, 58% were women, 41% of participants were overweight and 59% were considered obese. Baseline data suggested participants spent a mean of 10.04 (SD, 1.01) hours per day engaging in sedentary behavior, a mean of 1.79 (SD, 0.59) hours per day standing, a mean of 1.74 (SD, 0.44) h/ day in light-intensity physical activity, and 0.97 (SD, 0.32) hours per day in moderate-to-vigorous physical activity, took a mean of 5149 (SD, 1825) steps per day, and experienced a mean of 29 (SD, 8) breaks in sedentary behavior daily. Of the 64 patients selected for inclusion, 33 were randomized to the intervention and 31 were randomized to the control arm of the study, with these patients receiving instruction to maintain usual lifestyle habits.

At the end of the trial, results suggested those in the intervention arm experienced a reduction in sedentary behavior of 50 (95% CI, 24 to 73) minutes per day, with this being driven by an increase in light-intensity and moderate-to-vigorous physical activity of 19 (95% CI, 8 to 30) and 24 (95% CI, 14 to 34) minutes per day, respectively. Investigators pointed out standing times increased among those in the intervention arm by 6 (95% CI, -11 to 23) minutes per day, but this difference failed to reach statistical significance. Investigators also noted baseline activity levels were maintained among those in the control arm throughout the duration of the trial.

Additionally, results of the investigators’ analyses indicated randomization to the intervention arm was associated with significant improvements in fating insulin (83.4 [68.7, 101.2] vs 102.0 [95% CI, 83.3 to 125.0] pmol/l), HOMA-IR (3.2 [95% CI, 2.6 to 3.9] vs 4.0 [95% CI, 3.2 to 4.9]), HbA1c (37 [95% CI, 36 to 38] vs. 38 [95% CI, 37 to 39] mmol/mol), and liver enzyme alanine aminotransferase (28 [95% CI, 24 to 33] vs. 33 [95% CI, 28 to 38] U/l) when compared to randomization to the trial’s control arm.

“To our knowledge, this is the first study to measure sedentary behavior and physical activity with accelerometers continuously throughout the 3-month intervention, and to investigate the health effects of SB reduction in sedentary and inactive, middle-aged adults with metabolic syndrome,” wrote investigators.

This study, “Effects of reduced sedentary time on cardiometabolic health in adults with metabolic syndrome: A three-month randomized controlled trial,” was published in the Journal of Science and Medicine in Sport.