The Daily Trip to the Gym Won’t Cancel Out the Adverse Effects of Sitting at your Desk All Day!

Research Paper Title

Sitting Time and All-cause Mortality Risk in 222 497 Australian Adults.Time for Change

Background

Prolonged sitting is considered detrimental to health, but evidence regarding the independent relationship of total sitting time with all-cause mortality is limited. This study aimed to determine the independent relationship of sitting time with all-cause mortality.

Method

The researchers linked prospective questionnaire data from 222,497 individuals 45 years or older from the 45 and Up Study to mortality data from the New South Wales Registry of Births, Deaths, and Marriages (Australia) from 01 February 2006 through 31 December 2010. Cox proportional hazards models examined all-cause mortality in relation to sitting time, adjusting for potential con-founders that included sex, age, education, urban/rural residence, physical activity, body mass index, smoking status, self-rated health, and disability.

Results

During 621,695 person-years of follow-up (mean follow-up, 2.8 years), 5,405 deaths were registered. All-cause mortality hazard ratios were:

  • 1.02 (95% CI, 0.95-1.09) for 4 to less than 8 hours per day of sitting.
  • 1.15 (1.06-1.25) for 8 to less than 11 hours per day of sitting.
  • 1.40 (1.27-1.55) for 11 or more hours per day of sitting.

Compared with less than 4 hours per day, adjusting for physical activity and other con-founders. The population-attributable fraction for sitting was 6.9%.

The association between sitting and all-cause mortality appeared consistent across the sexes, age groups, body mass index categories, and physical activity levels and across healthy participants compared with participants with pre-existing cardiovascular disease or diabetes mellitus.

Conclusions

Prolonged sitting is a risk factor for all-cause mortality, independent of physical activity. In other words, sitting all day then going to the gym does not make a blind bit of difference; you need to break up periods of sitting with periods of not sitting!

Public health programmes should focus on reducing sitting time in addition to increasing physical activity levels.

Reference

van der Ploeg, H.P., Chey, T., Korda, R.J., Banks, E. & Bauman A. (2012) Sitting Time and All-cause Mortality Risk in 222 497 Australian Adults. Archives of Internal Medicine. 172(6), pp.494-500.

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