Replacing 30 minutes per day of sedentary time with 30 minutes of physical activity at a light intensity was associated with a 17% lower risk of early death in a study published in the American Journal of Epidemiology on Monday.
The study also found that replacing 30 minutes of sedentary time with 30 minutes of moderate to vigorous exercise was associated with a 35% lower risk of early death.
“If you replace 30 minutes of sitting time with 30 minutes of light-intensity physical activity — so something just like a casual stroll down the hall — that still can lower your risk,” said Keith Diaz, a certified exercise physiologist and assistant professor of behavioral medicine at Columbia University Medical Center in New York, who was first author of the study.
“Obviously, it doesn’t lower your risk as much as exercise, or as much as moderate to vigorous physical activity, but it still can lower risk, and to us, that was somewhat of a new finding,” he said. “Any movement for any length of time is going to give you health benefit, and this is really shifting what we know about physical activity.”
The study included national data on 7,999 people age 45 and older who wore activity monitors to track their sedentary time between 2009 and 2013. The researchers used that data to analyze and simulate the mortality benefits that could be incurred if sedentary time in the data was replaced with physical activity.
The researchers found that replacing sitting time with exercise and movement was associated with a benefit, but replacing prolonged periods of sitting with shorter periods of sitting was not.
“In our previous work, we found that if you take a break every 30 minutes, it will lower your risk from sitting,” Diaz said, but the new study didn’t show that in the data.
“We went deeper into the data to try to understand that more, and why people who took a movement every 30 minutes had a lower risk of death: It’s because they just had more opportunity to move,” he said.
The new study had some limitations, including that the researchers found only an association between physical activity and a lower risk of early death, and the finding was based on simulations.
Overall, Diaz said, he hopes the findings help encourage people to become more active in their daily lives.
“You don’t have to take 10 minutes’ break and go run up and down the stairs,” Diaz said.
“If you take a 1-minute movement break and instead of going to the bathroom closest to your desk, you go to the bathroom furthest from your desk, maybe that’s enough to help you accrue this healthful activity,” he said. “Or, if you have a meeting, walk and talk.”
“In this article, they talk about replacing 30 minutes of total sedentary time with 30 minutes of light-intensity physical activity, and they saw a drop of 17% of lower mortality risk,” she said. “This is really encouraging and should be very encouraging to people.”