If you value your life, you should stand up and walk around right now. Too much time on the couch – or in the desk chair – can kill, according to a new study published in the Annals of Internal Medicine.
We already knew that the sedentary lifestyles becoming ever more common in post-industrial societies were bad for us, but the study by Keith Diaz at Columbia University and colleagues draws a grim and direct connection between lack of movement and death.
The researchers studied almost 8000 Americans aged 45 and over to examine the relationship between sedentary behaviour and death for any reason (what researchers call “all-cause mortality”). While measuring all-cause mortality doesn’t tell you about the direct mechanisms that connect sitting down and dying, it does strongly suggest that some connection exists.
Previous similar studies have often relied on self-reported levels of activity, but this one had the participants wear an accelerometer that measured their movements over the course of the day in order to give an objective measure of sedentary time.
The study showed that on average people were sedentary for an alarming 12.3 hours of the 16 they were awake on a given day.
Over the roughly 4 years of the study, 340 participants died. The researchers found a “dose-response” relationship between the risk of death and the amount of sedentary time, which means that the more you sit the more your risk of dying goes up. The researchers say the effect is independent of other factors such as age, sex, race, BMI, and exercise habits.
As well as the total amount of sedentary time, the length of sitting bouts was also an important factor. People who kept their stretches of sitting to less than 30 minutes had the lowest risk of death.
An accompanying editorial suggests that our inactive lives represent evolutionary stagnation and that – rather than tracking our movements with FitBits or stopwatches – we might be better off turning back to the highly mobile lives of our hunter-gatherer ancestors.