Warnings about sitting too much because of its supposed health risk have become frequent in recent years. The idea is now so engrained in society that special stand-up desks have been made to provide an alternative while working. However, evidence regarding this relationship has always been tenuous, and now a new study claims that there may not be an actual link after all.
The study, published in International Journal of Epidemiology, finds that sitting time is not associated with all-cause mortality risk. The authors, from the University of Exeter in the United Kingdom, caution physicians on emphasizing sitting as a risk factor for mortality.
The researchers assessed the controversial link between sitting and mortality risk within a population of London-based civil servants. The context of sitting was assessed via self-reported data for five parameters: 1) sitting at work; 2) sitting while watching TV; 3) sitting during leisure time; 4) sitting during leisure time, excluding TV viewing; 5) sitting at work and leisure.
The study, which began in 1985, followed participants aged 35 to 55, for 16 years of follow up. In total, 450 deaths were recorded. Data for 3,720 males and 1,412 females were identified and utilized in the analyses. After accounting for confounders (including age, gender, alcohol consumption, smoking, diet, and vigorous physical activity) the study found that across those 16 years there were no associations between any of the five different types of sitting time and mortality from any cause.
What's notable is that the study doesn't confirm much of what's been published by other researchers on the topic, primarily that there's a link between mortality and prolonged sitting time.
The cohort of Londoners does identify as a group having a higher-than-average daily activity, which researchers say can contribute towards the disparity. Adding to its limitations, critiques of the study highlight the use of patient self-assessment of sitting, suggesting that it is not an objective methodology for investigation.
The study helps to make the distinction that we should not be vilifying people, as well as professions which require extensive sitting, but instead focus on the benefits of engaging in more physical activity. Essentially, the benefits of increased physical activity can stand on their own. However, recommending less time sitting should be put in context with overall physical activity.