Abstract
Background: Results from a recent body of research suggests that sedentary behaviour increases the risk of chronic disease (e.g. type 2 diabetes and cardiovascular disease) through negative effects on cardiometabolic risk factors (1-5). Breaking prolonged sitting with regular short bursts of activity (1-min 40 s to 2-min every 20- to 30-min) has been found to lower postprandial glucose and insulin concentrations (6-8). Yet, these trials have only examined short-term effects over one or two days, therefore there is a need to test the effect long-term (weeks to months). To do this, intervention strategies that lead to a sustained increase in the frequency of regular activity breaks in sedentary dominated environments (e.g. the workplace) are required. Furthermore, before conducting a large-scale trial, more information is needed to identify and address possible negative outcomes associated with this strategy, in order to tailor interventions accordingly and safely maximise on the health benefits.
Objectives: The primary aim of the feasibility study was to limit occupational sedentary behaviour through the inclusion of regular activity breaks. The secondary aims of the study were to assess the impact regular activity breaks has on; dietary snacking patterns, and musculoskeletal discomfort, fatigue, and work productivity. Overall, this study was used to explore the viability of assessment methods and tools to be used in a larger intervention trial.
Design: A convenience sample of 12 employees were recruited from the University of Otago to participate in the uncontrolled feasibility intervention trial. Participants were asked to perform 2-min of low to moderate physical activity every 30-min throughout their working day for five weeks. Regular activity breaks were measured using accelerometry at baseline, and intervention weeks 1, 3, and 5. At the end of these weeks, musculoskeletal discomfort, fatigue and productivity were measured using three questionnaires; Standardised Nordic Questionnaire (SNQ), Individual Strength Questionnaire (ISQ) and Health and Work questionnaire (HWQ). Diet was measured using a snacking questionnaire and three 24-hour recalls at baseline and end of weeks 3 and 5.
Results: The mean (SD) number of activity breaks taken per day by participants at baseline was 12.4(1.8) this increased significantly by 3.3 (95% CI: 2.4, 4.3; P<0.001) to 15.8 (2.7) at week 5. Interestingly, over this time, a downwards trend was observed in both weekly snacking and total daily snacking. Overall, weekly snacking in the evening decreased by three snacks (95% CI: -0.20, -5.80; P= 0.038) and daily total snacking decreased by one snack, (95% CI: -2.7, 0.72; P=0.032) respectively. This decrease was reflected in total energy and macronutrient intake reductions over the five-week intervention, as assessed by 24-hour recall.
Conclusion: Participants were undertaking an unexpectedly high number of breaks at baseline, 12.4, thus, the goal of 16 was easily attainable, which majority achieved. This suggests that either the defined cut-offs for activity breaks were too low or that participants were less sedentary than what they initially perceived. Consequently, this slight increase in regular activity breaks meant only a small association between increased activity breaks and reduced snacking could be concluded. It is likely the dietary changes observed were the result of regular dietary assessment and/ or personal weight loss motives. Due to the potentially confounding effects ‘unfavourable’ food intake may have on the health benefits of regular activity breaks it is recommended diet outcomes continue to be considered alongside research investigating regular activity breaks.