More than half of Americans’ waking hours are spent sitting — at the computer, in front of the TV, commuting to work. Studies have found a connection between the amount of time a person spends sitting and conditions such as heart disease, type 2 diabetes, and cancer, independent of the participants’ level of physical activity. But how this risk is affected by physical activity has been unclear.
Most public health campaigns typically focus on getting more exercise. Rarely do health initiatives encourage people to spend less time seated. The findings of a new Canadian study suggest, however, that sitting for long periods of time is strongly associated with negative health outcomes, regardless of how physically active a person is. Maybe it's time for a new approach?
“We need to target sedentary behavior and physical activity separately, or they need to be combined in a public health message,” Avi Biswas, lead author on the paper, told TheDoctor.
You can be incredibly active but that doesn’t mean you will be sitting less during the day.
You can run a couple of miles a day, but if you spend hour upon hour sitting at your desk and in front of the TV, you are still risking your health.
The researchers analyzed data from 47 studies that looked at the link between sitting and at least one health outcome: cancer, heart disease, or type 2 diabetes. They found that, independent of physical activity, sitting was strongly associated with death from all causes and the incidence of heart disease, certain cancers (breast, colon, colorectal, epithelial ovarian, and endometrial), and type 2 diabetes in adults.
The level of a person's physical activity did have some good effect: as activity increased, the strength of the link between sitting and these health conditions decreased.
“The way to think about it is that all the hours in our waking day add up to our health, it's not just the one hour or 30 minutes that we put into exercising,” said Biswas, a Ph.D. candidate at the University of Toronto. “If you can make small changes, it all adds up. For example, instead of sitting on the bus or subway, choose to stand. Standing doubles your metabolic rate or calories burned.”
Having established that sitting, even among those who are physically active, is associated with serious health risks, the next step, Biswas added, is to develop an intervention that targets sedentary behavior. In the meantime, you may want to set the timer on your phone to alert you every half-hour, so you remember to get up and move around.