Prolonged sitting is bad for your health but there's a way to mitigate the risk, study finds

A person using a laptop. (Pexels)

Sitting more than eight hours a day can increase the risk of heart disease and early death by 20 per cent, according to a new study co-authored by a B.C. professor.

Research carried out by Simon Fraser University's Scott Lear and Wei Li of Beijing’s Chinese Academy of Medical Science tracked 100,000 people in 21 countries over 11 years to try to get more insight into the dangers of prolonged sitting.

"Sitting is bad for us, and that's nothing new," Lear told CTV News, explaining they were trying to measure, in part, whether increased physical activity could mitigate the ill effects.

The risk of early death and heart disease increased further among those who spent even more time sitting and did the least activity, the research found. Physical activity, even for those who did the most sitting, brought the risk down. "Those people who were highly active had much lower risk, and even had lower risk than those people who are sitting for four hours a day without doing physical activity," he explained.

'IT'S MOVEMENT THAT MATTERS'

Lear says the amount of activity required to offset the potential damage done is fairly easy to achieve but awareness is lacking. Further, he says only one in four Canadians meet the daily activity guidelines.

So what does he suggest?

"A three-minute walk, whether it's light or moderate walking, it doesn't matter, every 20 or 30 minutes," he says.

"Get up, do something, walk around. Movement is important. Standing isn't much different than sitting, it's just a different posture. It's movement that matters."

He also says the study found that for those sitting more than four hours a day, replacing a half-hour of sitting with exercise reduced the risk by two per cent. For those who sat more than eight hours per day, being active for an hour was enough to reduce risk to those who sat only four hours a day but were not active.

While public health messaging that "sitting is the new smoking" isn’t exactly true, Lear says there's not a very significant difference between the health impacts.

"When we looked at the combination of sitting and low-activity, those things accounted for just under nine per cent of deaths over the 11 years. Smoking accounted for 10 .6 per cent," he said.

"That combination of physical inactivity and high sitting wasn't quite at the same level but it was close to smoking. That's an important message also to get out for health professionals and clinicians. Because working with a patient to increase their activity, or get them to break up their sitting is a pretty low-cost intervention that can have substantial benefits."

Explaining why sitting is so bad, Lear uses a metaphor of a car that automatically stops running when stopped at a red light.

"Our bodies are efficient machines and when we're not using it, things shut down. What happens, especially, is that proteins that are used to break down sugar and fat from the blood for our muscles to use as energy get shut down because we're not moving. So why do we need that energy?"

This is why, Lear says, it's particularly important not to remain sedentary in the hours immediately following a meal. It's also why other studies have found that TV-watching is one of the worst kinds of sitting, because it's so often paired with snacking.

While the study didn’t look at whether a switch to remote work during the pandemic impacted risk, Lear says people who work from home should be mindful that they may be moving less than they were when they went into the office.

"Some people are more productive at home just because they're sitting and working more as opposed to being interrupted, going to the water cooler or photocopier or whatever. It's easier to kind of sit (in one place)," he says.

Some strategies he says he's found helpful are getting up and walking around when talking on the phone setting an alarm for every half hour as a reminder to get up and move. At home, small chores like emptying the dishwasher can also provide an opportunity to walk away from one's desk.