Sedentary behaviors recently came under fire after several studies linked more time spent sitting with a higher mortality risk, even for people who exercise. Researchers from the University of Exeter, in England, believe that those studies were flawed and that active individuals who also
sit a lot may not face a greater risk of early death after all.
The Exeter researchers
conducted their own study, featuring 3,720 men and 1,412 women, aged 35–55,
all employees of the British Civil Service in London.
Over nearly 16 years, these participants completed questionnaires about occupational and leisure-time sitting behaviors and underwent clinical examinations.
The researchers used five sitting categories: work sitting, TV viewing time, non-TV leisure-time sitting, total leisure-time sitting
and total sitting time. Other variables that were monitored included moderate to vigorous physical activity (MVPA); body weight and body mass index; nutrition and alcohol intake; and more.
During the study, 450 people died. But the
researchers could not determine a link between these deaths and any of the five sitting categories.
“The present study tested the hypothesis that sitting time would predict mortality risk independently of MVPA and [that] associations would vary by type of sitting,” the authors stated. “Across almost 16 years of follow-up, no prospective associations were observed between five different indicators of sitting time and mortality from all causes.”
Sitting times in the current study were equal to those in the studies that found sedentary behavior was harmful even for exercisers. Essentially, this new study indicates that
sitting time might not have a negative impact on active individuals. However, the authors did note that participants in this study reported higher levels of walking than those recorded in the earlier studies.
“The findings may be due in part to a protective effect of a higher than average energy expenditure
due to the habitual active transport associated with London-based employees,” the authors said. In other words, Londoners may benefit from walking more than average on their way to and from work.
The study appeared in the International Journal of Epidemiology (2015; doi: 10.1093/ije/dyv191).