Sitting for six hours or more a day increases your risk of early death by 19 percent compared to those who sit less than three hours a day, per a new study by the American Cancer Society.
The paper, published in the American Journal of Epidemiology, analysed data pooled from more than 127,000 US adults over a 21-year period.
Spending the majority of your leisure time sitting was linked to a higher risk of death from an alarmingly long list of conditions: cancer, coronary heart disease, stroke, diabetes, kidney disease, suicide, lung disease, liver disease, peptic ulcer and other digestive disease, Parkinson’s disease, Alzheimer’s disease, nervous disorders, and musculoskeletal disorders.
“While we still have yet to understand how to quantify what a safe amount of sitting time may be, what is clear is that individuals should take any opportunity to take breaks in sitting time and cut down sitting time to whatever degree they can,” said the study’s lead author American Cancer Society senior scientific director Dr Alpa Patel, in a statement.
Why is excess sitting so bad for you?
The study didn’t probe why increased sitting time is linked to an increased risk of early death, although Patel and her team offered a few possible reasons.
The first is straightforward: the more time you spend sitting, the less time you spend moving, so therefore the less likely you are to earn the many, many, many health benefits of physical activity.
It’s also likely that people who spend a lot of time sitting — watching TV, or playing video games — may have other unhealthy lifestyle habits, like excess snacking. (How many times has a Netflix binge coincided with polishing a whole bag of peanut M&M’s?)
Time spent sitting also has a negative physiological effect — that is, your body just doesn’t function as well when it’s not moving.
That was illustrated by an intriguing experiment published in Scientific Reports in June, in which Dutch researchers gathered 61 volunteers of varying weights and put them three different movement protocols for four days each.
On the Sit regimen, participants sat for 14 hours a day (almost all their waking hours); on the Exercise regimen they swapped an hour of sitting for an hour of moderate-to-vigorous cycling on a stationary bike, and sat the other 13 hours; on the SitLess regimen they traded about six hours of sitting for low-intensity walking or standing.
The results indicated that both moderate-to-vigorous physical activity and light physical activity improved different markers of health — in short, that you need to both exercise and spend more time on your feet for optimum health.
How to sit less
It’s sitting for long, interrupted stints of 30 minutes or more that appears to be bad for us — so bad, in fact, that even regular exercise might not undo the damage they cause (unless you’re accumulating about 80-90 minutes of moderate-intensity activity a day… which most of us don’t).
“This is because when we sit – as opposed to being upright and moving – the large muscles of the lower body are essentially ‘switched off’ and the amount of blood circulating through to our lower limbs slows dramatically,” wrote David Dunstan, a Baker Institute professor who researches the impact of too much sitting, for SBS Insight.
“The biological consequences of this are disruptions to the efficiency of our body’s metabolic and cardiovascular processes, such as maintaining optimal blood sugar and blood pressure levels.”