Reducing Sedentary Time and Whole-Body Insulin Sensitivity in Metabolic Syndrome: A 6-Month Randomized Controlled Trial

Abstract

Purpose: This study aimed to investigate whether a reduction in daily sedentary behavior (SB) improves insulin sensitivity in adults with metabolic syndrome in 6 months, without adding intentional exercise training. Methods: Sixty-four sedentary inactive middle-age adults with overweight and metabolic syndrome (mean (SD) age, 58 (7) yr; mean (SD) body mass index, 31.6 (4.3) kg•m −2 ; 27 men) were randomized into intervention and control groups. The 6-month individualized behavioral intervention supported by an interactive accelerometer and a mobile application aimed at reducing daily SB by 1 h compared with baseline. Insulin sensitivity by hyperinsulinemic euglycemic clamp, body composition by air displacement plethysmography, and fasting blood samples were analyzed before and after the intervention. SB and physical activity were measured with hip-worn accelerometers throughout the intervention. Results: SB decreased by 40 (95% confidence interval, 17-65) min•d −1 , and moderate-to-vigorous physical activity increased by 20 (95% confidence interval, 11-28) min•d −1 on average in the intervention group with no significant changes in these outcomes in the control group. After 6 months, fasting plasma insulin decreased (~1 mU•L −1 ) in the intervention group compared with the control group (time-group, P = 0.0081), but insulin sensitivity did not change in either group. The changes in body mass or adiposity did not differ between groups. Among all participants, the changes in SB and body mass correlated inversely with the change in insulin sensitivity (r = −0.31, −0.44; P = 0.025, 0.0005, respectively). Conclusions: An intervention aimed at reducing daily SB resulted in slightly decreased fasting insulin, but had no effects on insulin sensitivity or body adiposity. However, as the change in insulin sensitivity associated with the changes in SB and body mass, multifaceted interventions targeting to weight loss are likely to be beneficial in improving whole-body insulin sensitivity.

Effects of reducing sedentary behavior on cardiorespiratory fitness in adults with metabolic syndrome: A 6‐month RCT

“…The accelerometry results of this study have been reported and discussed earlier. 15 The INT group reduced SB by 40 min/day and increased MVPA by 20 min whereas in the CON group SB and MVPA remained unchanged (group × time p < 0.05). 15 Furthermore, daily step count increased in both groups but significantly more in the INT group (group × time p = 0.001).…”

“…As reported earlier, baseline SB and PA were measured for 4 weeks (screening phase), and thereafter during the whole 6-month intervention. 15 Triaxial accelerometers attached to the right hip were used (UKK AM30, UKK Terveyspalvelut Oy, Tampere, Finland during screening, and Movesense, Suunto, Vantaa, Finland during the intervention). The participants were advised to wear the accelerometer during waking hours and to remove it when going to sleep or when the device could be exposed to water.…”

“…The details of the accelerometer measurements have been reported elsewhere. 15 2.2.2 | Cardiorespiratory fitness CRF was evaluated by a graded maximal exercise test before and after the six-month intervention period on a recumbent cycle ergometer (eBike EL Ergometer with Case v6.7; GE Medical Systems Inc.). A recumbent cycle ergometer was used because echocardiography was also obtained during the exercise test (echocardiography is not reported here).…”

“…The intervention has been described in more detail previously. 15 The aim of the intervention was to reduce SB by 1 h/day compared to the individually determined baseline during the screening phase. The INT participants were instructed by a physiotherapist at a 1-h counseling visit to replace SB with LPA, MVPA, and standing.…”

“…21 Individual daily PA and SB goals were set on the application: for the CON group the goals were equal to the results measured during screening phase, and for the INT group 1 h was reduced from SB and an equivalent amount of time was added to LPA, MVPA and standing, according to individual preferences, as described previously. 15 However, a maximum of 20 min was added to MVPA. Adherence to the intervention in was assessed by calculating the percentage of measurement days when ≥1 h SB reduction was achieved.…”