For inactive middle-aged and older people with multiple health problems, being sedentary does appear to be linked to an increased risk of early death. But sitting a lot doesn't seem to affect active people the same way, the researchers said.
"We found that in people who scored low on the frailty index, sitting time was not linked to risk of death," said one of the study's authors, Olga Theou.
Still, she said, "Physicians should stress the harms of inactivity with patients, similar to the harms of smoking, to encourage movement." Theou is an assistant professor with Dalhousie University in Halifax, Nova Scotia.
"Even something as simple as getting up and walking around the house with a walker or cane can benefit frailer people," she suggested.
The study included data from more than 3,100 adults who participated in a U.S. health survey. All of the participants were aged 50 and over, and were followed from the mid-2000s until 2011.
The study participants' movements were monitored with the help of activity trackers. The researchers also used a questionnaire to figure out how frail the participants were based on the number of medical problems they had.
The report was published in the Aug. 21 issue of the CMAJ (Canadian Medical Association Journal).
"Prolonged sitting was associated with a higher risk of death only in vulnerable or frail people who did not meet the weekly recommendation for 2.5 hours of moderate physical activity," Theou explained in a journal news release.
And while the study found an association between inactivity and increased risk of early death in frail people, it couldn't prove a cause-and-effect relationship.
SOURCE: CMAJ (Canadian Medical Association Journal), news release, Aug. 21, 2017