Sedentary lifestyle and healthy aging: what does the research say?

It's tempting to binge-watch TV, but another study suggests that for healthy aging, the less time you spend on the couch, the better.

The study analyzed 20 years of data from more than 45,000 participants. All of them were over 50 years of age in 1992 and had no chronic diseases at the time of entry into the study.

The researchers tracked habits such as time spent sitting at work, at home and in front of the TV, as well as hours spent standing or walking at home or at work. All of this data was compared with information about how well (or not) the participants aged over time.

What is “healthy aging”? According to a team from the T.H. School of Public Health. Chan University of Harvard University, this meant living to age 70 or more without major chronic diseases, without memory impairment, and in generally good physical and mental health.

One activity—watching TV while sitting—was particularly unhealthy, the researchers found.

"Replacing TV time with light physical activity, moderate-to-vigorous physical activity, or sleep [in sleep-deprived participants] was associated with better odds of healthy aging," wrote a team led by Dr. Molin Wang, an assistant professor of medicine in Harvard's department of epidemiology..

More specifically, every hour a day that sedentary time in front of the TV was replaced by even “light” physical activity at home (such as routine household chores) increased a person's chances of living to a healthy age of 70 or more by 8%.

If that hour of TV watching was replaced with “moderately intense” physical activity (such as working out), the chances of healthy aging increased by 28%, the study found.

Even people who slept less than the recommended seven hours a night saw healthy aging benefits if they added an extra hour of sleep each day instead of an hour spent watching TV on the couch.

The study results were published in JAMA Network Open.

In an interview with CNN, Dr. Andrew Freeman, director of cardiovascular disease prevention and wellness at National Jewish Health in Denver, said watching TV seems like a particularly unhealthy activity—and not just because you're not moving.

"When people sit in front of the TV, it is usually accompanied by other unhealthy activities, such as eating junk food, ready-made dinners, lack of interaction with other people and even sleep disturbances," Freeman noted. He did not participate in the new study.

And physical exercise - in any form and for any period of time - can change this situation. It's "a truly incredible way to reduce your risk of heart disease and blood pressure," Freeman said.

“My very strong advice is at work, if possible, use a standing desk or even a treadmill if you have the ability and space,” Freeman said. “If you're sitting for more than 30 minutes at a time, that's too long in my opinion and you should really try to move around a little.”