Excess sedentary time causes sickness

Spending several hours a day sitting in front of a computer or television screen can have negative consequences for your health, prof says

Sedentary time can be harmful even with regular exercise
Image by: Justin Tang
Sedentary time can be harmful even with regular exercise

In a society where accessing a laptop or TV can be as easy as snapping your fingers, we’re subject to spending hours at a time facing a screen. Facebook, YouTube and the ability to stream just about any television show online means that we probably don’t notice the time as it passes us by.

A study published this month by University College London in the Journal of the American College of Cardiology showcases a link between an increase in the risk of heart disease and spending too much time in front of a screen. How much time is too much, though? The study says that even a mere two hours of screen time can increase the likelihood of heart attack, stroke or even heart failure.

Ian Janssen, assistant professor in the School of Kinesiology and Health Studies, said there’s definitely a connection between health and amount of sedentary time. Janssen described sedentary time as the time spent doing activities such as sitting down in front of a computer or TV screen or sitting down to eat.

“[The] more screen time, and in particular sitting time or sedentary time, the worse off the individual will be,” Janssen said, adding that sedentary time can be harmful even for those who are regularly active.

“In other words, if you take an active person who does 30 minutes a day, 5 days a week of moderate to vigorous activity, and they’re more sedentary in the rest of the day than another active person, that person who is sedentary the rest of the day will have a worse health outcome,” he said.

The University College London study also concluded that physical activity may not reverse the effects of hours a day of sedentary time.

Janssen said two recently published papers measured how much time a day Canadians are sedentary by giving participants motion sensors to wear. The participants, age six to 79, wore the sensors for a week.

“We were able to capture how active people were so you can measure sedentary time,” he said. “Part of what that study suggests is that the average adult in Canada spends 69 per cent of their waking hours … sedentary.”

The paper broke the participants down into age groups. The 20-39 age group spent 9.5 hours a day sedentary, not including the time they spent asleep.

According to Janssen, research has shifted in the last five to 10 years from concentrating solely on how much physical activity a person gets to also examining what they do with the rest of their day.

“We’re starting now to recognize that the amount of activity that you’re doing when you’re not in moderate to vigorous activity … does have independent effects on one’s health,” Janssen said.

Amin Nikdel, ArtSci ’13, said he spends about three to four hours per day in front of a screen. He is a biomedical computing student, so for him, screen time is virtually unavoidable.

“Everything we do in class is on your laptop or on a screen,” he said, adding that he doesn’t see the negative health consequences of sitting in front of a screen as long as it’s balanced with physical activity, which is likely an opinion many students share.

“I go to the gym everyday and I still do walk around during the labs,” Nikdel said, adding that he advocates healthiness and tries to get his friends to accompany him to the gym from time to time.

Janssen divides screen time into two parts: occupational and recreational. Occupational screen time is unavoidable, according to him. Neglecting to write your final essay because it would mean too much screen time probably wouldn’t make your professor very happy.

There are a multitude of occupations where spending time in front of a screen is virtually unavoidable. Students, especially, can spend great portions of their waking hours in front of a computer screen.

Janssen said recreational screen time is where change can happen. The average Canadian adolescent, according to Janssen, spends about 6 to 7 hours of recreational screen time per day.

“[With university students] it’s probably similar, so there’s a lot of that free time or recreational time where you can certainly reduce or replace those screen time habits—in particular television which seems to be the worst of all evil—with other activities that are less sedentary,” Janssen said. “[That’s] where you’re going to have the most effect, where people can actually control things.”

Janssen suggests students set limits on TV time.

“Television is actually more sedentary than the computer, where you type away, or, if you’re playing video games, your hands are moving,” Janssen said, “[When you’re in front of the] television, you’re expending the same amount of calories as you are when you’re sleeping, which is as low as you can get.”

Unfortunately, there’s no concrete way to completely reverse the health effects of spending too much time in front of the screen. The only thing you can do is stop further harm, Janssen said.

“The first goal is not to turn 180 degrees and go the opposite direction, it’s just to stop any further increase any risk, because you can do that—change your behaviours for the better.”

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