A new study, which published in June in the Journal of Applied Physiology finds that sitting for hours slows the flow of blood to our brains. This has serious implications for long-term brain health. But there’s good news, getting up and strolling for just a couple of minutes every half-hour can stave off this decline in brain blood flow and may even increase it.
Delivering blood to our brains is essential for life and cognition but you probably never think about it. Brain cells need oxygen and nutrients that can only be supplied by good blood flow. Because blood flow is so necessary, the brain keeps the flow rate within a very narrow range. But fluctuations do occur, and can have serious repercussions. Studies in both people and animals show that drops in brain blood flow can temporarily cloud thinking and memory and longer-term declines have been linked to higher risks of neurodegenerative diseases, including dementia.
There is a lot of research showing that uninterrupted sitting decreases blood flow to various parts of the body. Most of those studies looked at the legs, which are affected the most by sitting. Sit for several hours, and blood flow to the legs is compromised.
In this new study published in Journal of Applied Physiology, researchers at Liverpool John Moores University in England gathered 15 healthy, adult, male and female office workers who had spent long hours sitting at a desk. The researchers brought these men and women to the university’s performance lab on three separate occasions. During each visit, they were fitted with specialized headbands containing ultrasound probes that track blood flow to the brain.
The subjects also breathed briefly into masks that measured their carbon dioxide levels at the start of the session, so that scientists could see whether levels of that gas might be driving changes in brain blood flow. Blood carbon dioxide levels can be altered by changes in breathing, among many other factors. The subjects then spent four hours simulating office time by sitting at a desk and reading or working at a computer. During one of these sessions, they never rose unless they had to visit the bathroom, which was close by. During another visit, they were directed to get up every 30 minutes and walk on a treadmill (that had been placed by their desks) for two minutes at whatever pace felt comfortable, the average speed turned out to be two miles an hour. In a final session, the subjects left their chairs after two hours and walked on the treadmills for eight minutes at the same gentle pace.
Scientists tracked the blood flow to the brains of the test subjects before and during each walking break, as well as immediately after the four hours were over. They also rechecked people’s carbon dioxide levels during those times.
As expected, brain blood flow dropped when people sat for four continuous hours. The decline was small but noticeable by the end of the session. Blood flow decline in the brain was equally apparent when people broke up their sitting after two hours, although blood flow rose during the actual walking break, it quickly sank again. But the scientists found that brain blood flow rose slightly when the four hours included frequent, two-minute walking breaks.
Interestingly, the scientists determined that none of these changes in brain blood flow were dictated by alterations in breathing and carbon dioxide levels. Carbon dioxide levels had remained steady before and after each session. So something else about sitting and moving was affecting the movement of blood to the brain and it had to be exercise.
While this study was small and short-term the results provide one more reason to avoid long bouts of sitting says Sophie Carter, a doctoral student at Liverpool John Moores University, who led the study. The researchers advise that breaks can be short but need to be recurrent. “Only the frequent two-minute walking breaks had an overall effect of preventing a decline in brain blood flow,” Carter says.
While the results of this study suggest two minute walking breaks every 30 minutes will help maintain good blood flow to the brain, the data gathered points to continuous walking as the idea solution for keeping the brain nourished and thus a clear agile state of mind.
Ideally you can buy an UnSit Treadmill Desk but if not, set your phone to beep every half-hour then get up and walk down the hall, hike a flight of stairs or take a few laps around your office.
Your brain and your body will thank you.