A new study suggests that not all types of sitting are equally unhealthy.

Researchers at Columbia University have found that excess time spent sitting while watching TV can be linked to a greater risk of cardiovascular disease and early death than sitting at work.

According to the study, people who sit in a sedentary behaviour -- long, uninterrupted periods of time without any movement -- were found to have a higher risk of cardiovascular disease including heart attacks and strokes.

"Our findings show that how you spend your time outside of work may matter more when it comes to heart health," said study author and assistant professor Keith M. Diaz in a press release. "Even if you have a job that requires you to sit for long periods of time, replacing the time you spend sitting at home with strenuous exercise could reduce your risk of heart disease and death."

The study found that participants with the most TV-watching hours (4 or more hours a day) had a 50 per cent greater risk of cardiovascular disease and early death than compared to those who watched less than 2 hours of television a day.

In contrast, those who sat the most at work had the same health risks as those who sat the least.

The study, published Wednesday in the Journal of the American Heart Association, monitored 3,592 African-American participants for nearly 8.5 years. The participants self-recorded their television habits, hours spent sitting at a desk and exercise levels.

While the study focused on African-American adults, researchers say the findings may be applied to anyone who is sedentary.

"It may be that most people tend to watch television for hours without moving, while most workers get up from their desk frequently," said Diaz. "The combination of eating a large meal such as dinner and then sitting for hours could also be particularly harmful."

Diaz acknowledged that more research is needed but suggested that even the most dedicated TV watchers could benefit from going for a walk between binging episodes.

The study reported no increased risk in participants with the most TV-watching hours who exercised for at least 2.5 hours or more a week.

The study found occupational sitting was less problematic, but Diaz warned workers should still be wary of sitting too long in the office.

"We recognize that it isn't easy for some workers, like truck drivers, to take breaks from sitting, but everyone else should make a regular habit of getting up from their desks,” he said. “For those who can't, our findings show that what you do outside of work may be what really counts."