Dr. Nicolle Kraenkel
Does physical activity attenuate, or even eliminate, the detrimental association of sitting time with mortality? A harmonised meta-analysis of data from more than 1 million men and women.
Ekelund U, et al.
Lancet. 2016. pii: S0140-6736(16)30370-1. doi: 10.1016/S0140-6736(16)30370-1. [Epub ahead of print]
Daily sedentary time, e.g. PC work or TV watching, as well as physical exercise both influence cardiovascular as well as all-cause mortality [1, 2]. Yet, their interaction between each other and the resulting combined effect on mortality have been unclear so far.
In their recent meta-analysis, Ekelund and colleagues have conducted a meta-analysis of 16 prospective studies covering over 1 million individuals in total, analysing the association of daily sitting time and weekly physical activity (time x intensity) with all-cause as well as cardiovascular mortality .For persons exercising less than 35 MET-h per week (e.g. 5h of strenuous sports or >8h of moderate intensity exercise), all-cause as well as cardiovascular and cancer mortalities increase with daily sitting time. Interestingly, though, high weekly exercise activity (over 35 MET-h per week) could offset the detrimental effects of even > 8h daily sitting time . Moreover, even in persons in the lowest quartile of time spent sitting (< 4h/day), low exercise activity (< 2.5 MET-h per week) resulted in a significantly higher mortaliy as compared to highest activity/lowest sitting time group .
Similar results were obtained when data were analysed for daily TV watching time instead of overall sitting time. Interestingly, for persons of the highest exercise activity group, even TV watching times of up to 4h did not increase mortality risk, while in the lowest exercise quartile, mortality was significantly increased even with TV watching times under 1h per day .
The meta-analysis therefore underlines the importance of recreational sports and supports the recommendations of at least 30min-1h of physical exercise per day at moderate to high intensity in order to offset detrimental effects of long sitting time on mortality.
The content of this article reflects the personal opinion of the author/s and is not necessarily the official position of the European Society of Cardiology
1. IM Lee, EJ Shiroma, F Lobelo, P Puska, SN Blair, PT Katzmarzyk, Lancet Physical Activity Series Working Group. Effect of physical inactivity on major non-communicable diseases worldwide: an analysis of burden of disease and life expectancy. Lancet, 380 (2012), pp. 219–229
2. CP Wen, JP Wai, MK Tsai, et al. Minimum amount of physical activity for reduced mortality and extended life expectancy: a prospective cohort study. Lancet, 378 (2011), pp. 1244–1253
3. Ekelund U, Steene-Johannessen J, Brown WJ, Fagerland MW, Owen N, Powell KE, Bauman A, Lee IM; Lancet Physical Activity Series 2 Executive Committe; Lancet Sedentary Behaviour Working Group. Does physical activity attenuate, or even eliminate, the detrimental association of sitting time with mortality? A harmonised meta-analysis of data from more than 1 million men and women. Lancet. 2016. pii: S0140-6736(16)30370-1. doi: 10.1016/S0140-6736(16)30370-1. [Epub ahead of print]
Nicolle Kränkel, Charité – Universitätsmedizin Berlin, Berlin Germany
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