On average, adults in the United States are sedentary for 9 to 10 hours a day – a trend that has sparked concern among health experts and elicited a variety of potential strategies for mitigating the associated side effects.
To determine the health risks of extended sedentary time, a team of researchers studied nearly 8,000 black and white adults ages 45 and older and measured both their total and average lengths of sedentary time.
“The goal of our study was to determine what sitting habits are most hazardous: the numbers of hours in which a person sits overall in a day or sitting in really long, uninterrupted periods,” lead author Keith Diaz, an associate research scientist at Columbia University, told Courthouse News in an email.
While previous studies have attempted to measure the impact of sedentary time on negative health outcomes, many relied on self-reported data. Diaz and his team used a hip-mounted accelerometer to objectively measure bouts of sitting.
For the participants, sedentary time accounted for 12.3 hours a day over a 16-hour waking day. The average sedentary period was 11.4 minutes. In follow-ups performed over a median of four years, the team found that 340 participants had died.
Longer total and average sedentary time were both associated with higher risk for all causes of death, with the connection being dose-dependent. The observed association did not vary by race, sex, age, body mass index or level of exercise.
“We found that both habits, sitting for many hours in a day and sitting for long uninterrupted periods, were linked to an increased risk of death, regardless of whether a person exercised,” Diaz said.
In light of the findings, the team recommends taking a break from sitting every half hour to limit the negative effects of sedentary time.
“I think the key point to highlight is to move,” Diaz said. “The evidence for standing being a healthier alternative to sitting is not entirely convincing. So although standing desks are becoming more and more popular, until better scientific studies are published, I would encourage people who are concerned about their sedentary habits to take movement breaks as often as possible.”
The report was published Monday in the journal Annals of Internal Medicine.