Toronto Star: Research mounts to show ‘sitting is the new smoking’
Published on February, 20th 2014
By Dr. Greg Wells
ByTheresa Boyle Health Reporter, The Toronto Star
Regardless of exercise, too much sedentary time is linked to increased disability after age 60, new research shows.
New research showing a strong link between too much sedentary time and disability adds to growing recognition that “sitting is the new smoking.”
A study published Wednesday in the Journal of Physical Activity and Health found that for those 60 and older, every additional hour a day spent sitting is linked to a doubling of the risk of disability, regardless of the amount of moderate exercise the person gets.
Disability was defined as having limitations in ability to do basic activities such as eating, dressing, bathing, getting in and out of bed, and walking across a room.
While previous research has shown that a lack of exercise is a risk factor for disability, this is the first study to show that sedentary behaviour, in itself, is also a risk factor.
Take, for example, two 65-year-old women: one sedentary for 12 hours a day, the other for 13 hours. The second is 50 per cent more likely to be disabled, according to the study by Northwestern Medicine in Chicago.
Being sedentary is not just a synonym for inadequate physical activity, said lead author Dorothy Dunlop, a professor of medicine at the Northwestern University Feinberg School of Medicine.
“There are some unique things about sitting that could contribute to poor health. When you are sitting, you are using fewer muscles and your circulation slows down,” Dunlop explained in an interview.
The finding means that older adults need to reduce the amount of time they spend sitting, whether in front of a television or computer, regardless of how much moderate activity they do, she said.
“‘Sitting is the new smoking’ is a great tag line,” Dunlop said, noting there is more and more research to show that too much sitting contributes to obesity, heart disease and diabetes.
The study drew on data from the National Health and Nutrition Examination Survey from the U.S. Centers of Disease Control and Prevention. Looking at a sample of 2,286 adults aged 60 and older who wore accelerometers, it compared people in similar health who engaged in the same amount of moderately vigorous activity.
Moderate activity was defined as walking briskly, as if you are late for an appointment.
Because the study examined data at one point in time, it does not definitively determine that sedentary behaviour causes disability.
Greg Wells, a kinesiology professor at the University of Toronto, is not surprised by the findings. He said the study is consistent with many others published recently about the dangers of sitting.
“If you sit for eight hours a day, that actually damages your health, and if you do an hour of exercise in the evening, that’s great for you, but it doesn’t necessarily counteract the damage you are doing by being immobile,” he said.
Wells acknowledged that it’s difficult not to be sedentary in a society when so many people have desk jobs.
“The rule I recommend for people is 20-20. For every 20 minutes of sitting, get up and stretch for 20 seconds …. We just have to build in little, tiny bits of physical activity throughout the course of the entire day,” he said.
Wells said 85 per cent of the population does not get enough activity.
As little as 15 minutes of exercise — even just walking — is enough to “supercharge” the brain, he said.
“If you have something really important to do during the day, mentally it is great to do 15 minutes of exercise right before that,” Wells said, noting that it activates areas of the brain associated with learning, problem-solving, concentration and memory.