Standing or stepping instead of sitting favourably affects cardio-metabolic risk biomarkersLiterature - Healy GN et al., Eur Heart J. 2015
Replacing sitting time with standing or stepping: associations with cardio-metabolic risk biomarkers
Healy GN, Winkler EAH, Owen N I et al.,
Eur Heart J. 2015 First published online: 30 July DOI: http://dx.doi.org/10.1093/eurheartj/ehv308
In modern-day life, a large part of adults’ waking hours are spent sedentary; the average self-reported sitting time ranged from 3.2 to 6.8 hours/day across 32 European countries . ‘Too much sitting’ has been linked to cardiovascular disease, diabetes and premature mortality [2,3].
The cardio-metabolic benefits of ambulatory activity are well established , but the effect of standing as a non-ambulatory alternative to sitting is less well understood. Acute benefits of standing for postprandial glucose responses have been demonstrated [5,6], but non-acute relationships of standing with cardio-metabolic biomarkers are unclear. Also, existing evidence rarely considers that less time spent sitting inevitably increases the time spent in other activities. Isotemporal substitution takes into account such re-allocation of time from one activity to another. The type and intensity of activity that displaces sedentary time likely affects the benefits [7,8].
The current study applied isotemporal substitution when examining cross-sectional associations of sitting, standing and stepping with cardio-metabolic risk biomarkers, in adults wearing postural sensors (subsample from Australian Diabetes, Obesity and Lifestyle Study (AusDiab), a general population-based sample). Most participants provided >4 days of monitor data (n=678, 97%), and many all 7 days (n=572, 82%).
- After adjustment for confounders, each additional 2 hours/day spent time sitting was significantly associated with higher BMI (~3%), waist circumference (~2 cm), fasting plasma glucose (FPG, ~1%), total/HDL-c ratio (~5%), triglycerides (TGs) (~12%), 2h plasma glucose (~4%) and lower HDL-c (~0.07 mmol/L).
- Each 2h/day spent standing was significantly associated with lower FPG (~2%), total/HDL-c ratio (~6%), TGs (~14%) and 2h plasma glucose (~3%) and higher HDL-c (~0.07 mmol/L).
- Each 2h/day of stepping was significantly associated with lower BMI (~11%), waist circumference (~8cm), total/HDL-c ratio (~6%), TGs (~20%) and 2h plasma glucose (~14%) and higher HDL-c (~0.14 mmol/L).
- Associations of sitting, standing and stepping with cardio-metabolic biomarkers did not vary significantly with age or gender.
- Increased stepping time in conjunction with equivalent reduction of standing time was associated with lower BMI (~10%), waist circumference (~7cm) and 2h post-load glucose (~11%).
- 2 hours per day stepping instead of sitting was associated with lower BMI (~11%), waist circumference (~7.5cm), post-load glucose (~12%) and TGs (~14%) and higher HDL-c (~0.10 mmol/L).
- Standing instead of sitting was also associated with improved glucose and lipid profiles (2% lower FPG, ~6% lower total/HDL-c ratio, ~11% lower TGs and ~0.06 mmol/L higher HDL-c).
ConclusionThis study in community-dwelling adults shows that cardio-metabolic benefits may be achieved when sitting is reduced through increased time spent standing or stepping. Glucose and lipid metabolism were favourably affected already at durations shown to be feasible in workplace-setting interventions. Adiposity markers were only significantly improved when more time was spent stepping, instead of either standing or sitting.
Editorial comment Many studies have focused on the health benefits of moderate to vigorous physical exercise. More recently, attention has been devoted to sedentary behaviour as a cardiovascular risk factor. People who perform hours of vigorous physical activity per week may still spend long periods in sedentary mode, while other people may move all day long, without engaging any structured exercise. This may confuse the message that it is important to reduce sedentary lifestyle.
“This study, different from most studies assessing sedentary behaviour and health outcomes, measured sitting time objectively and did not rely on surveys to measure activity, providing a unique opportunity to assess accurately the potential metabolic benefit of standing vs. sitting.” (…) “Replacing standing by stepping resulted in better weight control but not necessarily in better atherogenic cholesterol ratios.” (…) “The results of this study have major public health implications and add to results of previous studies assessing the importance of avoiding sitting time and adding physical activity, even at levels of intensity that will not qualify for weekly goals of activity.” (…)”While pursuing exercise must continue as a recommendation for health promotion, it is clear that avoiding sedentary behaviour relies primarily on increasing nonexercise activity thermogenesis (NEAT) (energy expenditure, ed) more than on achieving weekly goals of exercise.”
Lopez-Jimenez points out the irony that today’s society facilitates sedentary behaviour and making less efforts, often under the name of comfort and convenience. Sedentary behaviour and environments promoting it are often considered as progress and economic power. Fortunately, a revolution against sitting seems to have started. Standing or stepping on a treadmill will likely become more common at the office, school and maybe the cinema or conferences. “The unintended consequences of modern life promoting sedentary behaviour can be reversed. Healthcare providers, policy makers, and people in general need to stand up for this. Literally.”
Find this article online at Eur Heart J
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