Count the number of hours you sit each day. Be honest.
“If you commute an hour in the morning and hour after work — that’s two hours, and if you sit at an eight-hour-a-day desk job that’s 10,” says epidemiologist Loretta DiPietro of the Milken Institute School of Public Health at George Washington University.
“Then you come home at, say, 6 p.m., eat dinner and crash into your recliner for another three to four hours,” says DiPietro. “That’s 13 to 14 hours of sitting.”
Being immobile like that for many hours each day does more than raise the risk of a host of diseases. DiPietro and her colleagues have good evidence that, as the years wear on, it actually reduces the ability of older people to get around on foot at all.
In a study of sitting and walking ability that surveyed people ages 50 to 71 across 8 to 10 years, those who tended to sit the most and move the least had more than three times the risk of difficulty walking by the end of the study, when compared to their more active counterparts.
Some ended up unable to walk at all. The study appears in the current issue of The Journals of Gerontology: Medical Sciences.
Prolonged sitting and TV watching were particularly harmful, DiPietro found, especially when combined with low levels of total physical activity. Young bodies may rebound from prolonged sitting with an hour at the gym, she says. But that seems less true in late middle age.
“Sitting and watching TV for long periods, especially in the evening,” she says, “has got to be one of the most dangerous things that older people can do.” And the period studied — the mid-1990s to 2005, or so — was even before the advent of rampant online streaming of shows, she notes. The problem today is likely even worse.
“Before binge watching, at least when a show ended you got up and walked around,” DiPietro says. “It’s now possible to watch several hours without moving.”
Though being sedentary at work is also a risk, office employees tend to at least get up now and then, walk down the hall to the printer or restroom, and go to lunch, she says. Or at least workers used to do that. Increasingly, she says, many of us of all ages are engineering much of that light activity out of our lives.
“We now use the Internet to go shopping, order groceries, send messages, and even gossip,” DiPietro says. “We used to walk down the hall and gossip; now we send it via email or text.”
To measure the effect of prolonged sitting on mobility, DiPietro and colleagues took data from the large NIH-AARP Diet and Health Study of men and women ages 50 to 71. The participants were all healthy when the study started in 1995 and 1996.
The researchers recorded how much those in the study watched TV, exercised or did gardening, housework or other physical activity at the beginning of the investigation. They included “light” physical activity like “puttering around, walking to get the mail, or walking to the car” says DiPietro.
The results: Those who watched five or more hours of TV per day had a 65 percent greater risk of reporting a mobility disability at the study’s end, compared with those who watched less than two hours per day. DiPietro says this association was independent of their level of total physical activity and other factors known to affect the ability to easily move around.
She offers an antidote: Get up at least every 30 minutes when staring at a screen.