Breaking Up Prolonged Sitting to Improve Cardiometabolic Risk: Dose–Response Analysis of a Randomized Crossover Trial

Abstract

PurposeSedentary time is ubiquitous in developed nations and is associated with deleterious health outcomes. Physical activity guidelines recommend reductions in sedentary time; however, quantitative guidelines that inform how often and how long sedentary time should be interrupted have not been provided. The purpose of this study was to examine the acute effects of multiple doses of a sedentary break intervention on cardiometabolic risk factors, concurrently evaluating efficacy of varying frequencies and durations of sedentary breaks.MethodsIn a randomized crossover study, middle- and older-age adults (n = 11) completed the following 8-h conditions on five separate days: 1 uninterrupted sedentary (control) condition and four acute (experimental) trials that entailed different sedentary break frequency/duration combinations: every 30 min for 1 min, every 30 min for 5 min, every 60 min for 1 min, and every 60 min for 5 min. Sedentary breaks entailed light-intensity walking. Glucose and blood pressure (BP) were measured every 15 and 60 min, respectively.ResultsCompared with control, glucose incremental area under the curve was significantly attenuated only for the every 30 min for 5-min dose (−11.8[4.7]; P = 0.017). All sedentary break doses yielded significant net decreases in systolic BP from baseline compared with control (P < 0.05). The largest reductions in systolic BP were observed for the every 60 min for 1 min (−5.2 [1.4] mm Hg) and every 30 min for 5 min (−4.3[1.4] mm Hg) doses.ConclusionsThe present study provides important information concerning efficacious sedentary break doses. Higher-frequency and longer-duration breaks (every 30 min for 5 min) should be considered when targeting glycemic responses, whereas lower doses may be sufficient for BP lowering.

Feasibility and Pilot Outcomes of the Move More @ Work Intervention Designed to Encourage Employees to be Physically Active for 2 Minutes After Every 30 Minutes of Sitting

“…Previous cross-sectional and longitudinal studies have identified interruptions or breaks in sedentary time in accelerometer data and investigated the relationships with health outcomes. [8][9][10][11] In comparison, to our knowledge this is the first workplace-based intervention study that has specifically attempted to define an interruption/activity break in a manner that more closely represents those used in laboratory studies that have shown significant health effects [17][18][19][20][21] and evaluate changes in this pattern of activity. We predefined that an OTM would be identified if the accelerometer data indicated that participants were not sitting (activPAL) and the ActiGraph data showed that counts per minutes had increased to greater than 1000 cpm, that was sustained for more than 1 minute and was preceded by ≥15 minutes of sedentary time (<150 cpm).…”

“…Carter et al 34 prompted people to move every 45 minutes, and their qualitative data suggested that people just disliked the computer prompt and lack of activity choices in the intervention, rather than the time frame for the prompt being an issue. A recent study comparing different sedentary break frequency/duration combinations of light-intensity walking found that greatest improvements in postprandial glucose and systolic blood pressure were achieved from moving for 5 minutes after every 30 minutes of sitting, with an interruption every 60 minutes for one also resulting in similar reductions in systolic blood pressure 21 . Duran et al 21 concluded that higher-frequency, longer-duration doses of light activity are necessary to target glycemic responses and should be used in future interventions.…”

“…A recent study comparing different sedentary break frequency/duration combinations of light-intensity walking found that greatest improvements in postprandial glucose and systolic blood pressure were achieved from moving for 5 minutes after every 30 minutes of sitting, with an interruption every 60 minutes for one also resulting in similar reductions in systolic blood pressure 21 . Duran et al 21 concluded that higher-frequency, longer-duration doses of light activity are necessary to target glycemic responses and should be used in future interventions. Our results suggest that in the workplace, this level of frequency/duration is not feasible; however, research has not tested whether a less frequent breaks (>30 minutes) but performed at moderate intensity could be efficacious on health outcomes and adherence.…”

“…21 Results showed that interrupting sitting time every 30 minutes with 5 minutes of light intensity walking attenuated both postprandial interstitial glucose responses and systolic blood pressure responses, while an interruption every 60 minutes for 1 minutes resulted in the largest decreases in systolic blood pressure. 21 Changes in these cardiometabolic outcomes are implicated in the development of cardiometabolic diseases. 7 Given the evidence between sedentary behavior and health, research that develops and investigates the feasibility and effectiveness of interventions to support behavior change and reduce sedentary behavior should be prioritized.…”

“…A recent study compared different sedentary break frequency/duration combinations of light intensity walking every 30 minutes for 1 or 5 minutes and every 60 minutes for 1 or 5 minutes 21 . Results showed that interrupting sitting time every 30 minutes with 5 minutes of light intensity walking attenuated both postprandial interstitial glucose responses and systolic blood pressure responses, while an interruption every 60 minutes for 1 minutes resulted in the largest decreases in systolic blood pressure 21 . Changes in these cardiometabolic outcomes are implicated in the development of cardiometabolic diseases 7 .…”