New research by Simon Fraser University is adding further weight to the argument that prolonged sitting may be hazardous to your health.

An international study surveying more than 100,000 individuals in 21 countries found that people who sat for six to eight hours a day had a 12-13 per cent increased risk for early death and heart disease, while those who sat for more than eight hours daily increased that to a sobering 20 per cent.

The study, co-led by Simon Fraser University health sciences professor Scott Lear and Wei Li of Beijing's Chinese Academy of Medical Sciences, is published on June 16 in the journal Jama Cardiology. Their research followed individuals over an average of 11 years and determined that high amounts of sitting time were associated with an increased risk of early death and cardiovascular disease.

While sitting was problematic in all countries, it was especially so in low-income and lower-middle-income countries. The overarching message here is to minimize how much you sit," says Lear. "If you must sit, getting in more exercise during other times of the day will offset that risk."

Not surprising, those who sat the most and were the least active had the highest risk -- up to 50 per cent -- while those who sat the most but were also the most active had a substantially lower risk of about 17 per cent.

"For those sitting more than four hours a day, replacing a half-hour of sitting with exercise reduced the risk by two per cent," Lear notes. "With only one in four Canadians meeting the activity guidelines there's a real opportunity here for people to increase their activity and reduce their chances of early death and heart disease."

The study found a particular association in lower-income countries, leading researchers to speculate that it may be because sitting in higher-income countries is typically associated with higher socioeconomic status and better-paying jobs.

Clinicians should focus on less sitting and more activity as it's a low-cost intervention that can have enormous benefits, Lear notes. But while clinicians need to get the message out about countering sitting with activity, individuals need to better assess their lifestyles and take their health seriously, Lear adds.

"Our study found that a combination of sitting and inactivity accounted for 8.8 per cent of all deaths, which is close to the contribution of smoking (10.6 per cent in Lear and Li's study). "It's a global problem that has a remarkably simple fix. Scheduling time to get out of that chair is a great start."