If you're sitting all day, science shows how to undo the health risks. Take 'activity snacks' every 30 minutes.
"People who walked for five minutes every half hour had lower blood sugar and blood pressure than those who sat continuously,
A short stroll every half hour may help undo the health harms associated with prolonged periods of sitting, a new study finds.
Mounting evidence has suggested that sitting for long periods of time — an inescapable fact of life for many workers — is hazardous to health even for those who exercise regularly.
In the new study, volunteers who got up and walked for five minutes every half hour had lower blood sugar and blood pressure than those who sat continuously. The researchers also found that walking for one minute every hour helped with blood pressure, but not blood sugar, according to the small study published in Medicine & Science in Sports & Exercise.
“If you have a job that requires you to sit most of the day or have a largely sedentary lifestyle, this is one strategy that could improve your health and offset the health harms from sitting,” said the study’s lead author, Keith Diaz, an associate professor of behavioral medicine at the Columbia University Vagelos College of Physicians and Surgeons.
It's not clear why sitting for long periods uninterrupted is bad for your health, but Diaz suspects at least part of the explanation is that while we’re sitting, we aren’t using our leg muscles.
“Muscles serve as important regulators of blood sugar levels,” he said. “If we don’t use them, things don’t work right.”
When it comes to blood pressure, moving around helps improve circulation, Diaz said. “When you’re sitting, the blood pools in the legs,” he added. “When you regularly activate the muscles in the legs, it helps restore regular blood flow.”
'Activity snacks' every 30 minutes
To look at the best way to battle the deleterious effects of sitting, Diaz and his team tested four different ‘activity snacks’ in 11 volunteers: one minute of walking after every 30 minutes of sitting, one minute after 60 minutes of sitting, five minutes after 30 minutes of sitting and five minutes after 60 minutes of sitting . The effects of each of those strategies were compared to those from sitting with no breaks.
Each of the 11 adult volunteers came to the researchers’ lab where they were seated in an ergonomic chair for eight hours, getting up only for a bathroom break and whatever activity snack they’d been told to perform. All 11 ran through each of the strategies, one at a time, as well as an eight-hour period in which they only got up for bathroom breaks.
Blood pressure and blood sugar were measured during each phase of the study. The strategy that worked best was five minutes of walking for every 30 minutes of sitting. This strategy also had a dramatic effect on how the volunteers’ bodies responded to large meals, producing a 58% reduction in blood pressure spikes compared with sitting all day.
All walking strategies resulted in a significant reduction of 4 to 5 blood pressure points, compared to sitting all eight hours. Every type of activity snack, except for walking one minute every hour, also led to significant decreases in fatigue and improvements in mood.
The study proves that walking helps, Diaz said, although he suspects some managers might frown on workers walking away from their desks.
“The next big important step for us is to change workplace culture,” he said.
How to take a walking break at work
“You might walk to a co-worker’s desk rather than sending an email,” he suggested. “If you’re on the phone, you could be walking. You could bring a smaller bottle of water to work so you have to keep getting up to refill it."
While the strategies suggested in the new study aren’t a replacement for regular exercise, they may help with the harms of prolonged sitting, said Dr. Ron Blankstein, a preventive cardiologist at Brigham and Women’s Hospital and a professor of medicine at the Harvard Medical School.
"We do know there’s a lot of harm in sitting," he said. "When you do it without breaks, your blood pressure goes up and there are elevations in blood sugar.”
Do standing desks help?
While standing desks have become a big thing, Diaz doesn’t recommend them.
“The science on standing desks is still largely mixed,” he added. “And there’s some evidence that they could potentially be harmful to your back and the blood vessels in your legs.”
Blankstein noted that "being in one position all day, whether it’s standing or sitting, is not good.”
The findings of the new study make sense, said Dr. Doris Chan, a general and interventional cardiologist at NYU Langone Health.
“I’m really happy this came out,” she said. “It could be the start of something revolutionary. We just need larger studies with more people. But this is like a seed that’s been planted. It opens doors to all kinds of other research.”
Getting up and walking every half hour might have other benefits, such as loosening joints that have stiffened after long periods of sitting, Chan said.
“I hope that employers read about this study and take to heart that they should be allowing their employees to take breaks to stretch and to move,” she said. “It might even improve workflow.”
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