It’s fairly well understood by now that prolonged sitting—whether at your desk, at the wheel or on the couch—can cause your muscles and joints to seize up and stiffen.
But research suggests it also affects your brain.
A 2018 study published in the Journal of Applied Physiology discovered that uninterrupted sitting caused a significant 3.2% reduction in blood flow velocity to the brain.
This decline in cerebral blood flow could explain why some tasks feel harder to crack the longer you dwell on them, or why reaction speed slows down on a long drive.
The research, led by Sophie E. Carter of Liverpool John Moores University, also found that this decline could be offset by taking regular light-intensity walking breaks.
“Simply breaking up sitting seems a helpful strategy,” says co-author Dick Thijssen, professor in cardiovascular physiology and exercise at Liverpool John Moores University.
“We have found that breaking up four hours of sitting with a few minutes of walking every 30 minutes is sufficient,” he tells Fit&Well.
“Specifically, this prevents the decline in vascular function and prevents the decline in blood flow to the brain that you normally see after four hours.”
At work this can be easily done by taking walking breaks, taking the stairs, visiting your colleagues physically rather than sending an email, or taking walking lunches or meetings, Thijssen advises.
If confined to your home office, you could even walk on the spot for two minutes, like the participants did during the study.
And what if you’re tied to your desk for more than four hours?
“Do what you can to prevent it,” Thijssen stresses, admitting this is not always possible.
“In that case, remember that any activity is better than none. Even fidgeting with your lower limbs can sufficiently activate the lower limb muscles to increase blood flow.”
About the study
In the study, the researchers noted that “decreased cerebrovascular blood flow and function” is associated with “lower cognitive functioning and increased risk of neurodegenerative diseases”.
To investigate how this could be protected against, Carter’s team monitored 15 healthy office workers over the course of four-hour spells as they were exposed to three different conditions.
Walking breaks were conducted on the spot at a normal, self-selected walking pace, and blood flow to the middle cerebral artery was measured at baseline and after four hours.
- Uninterrupted sitting: Triggered a 3.2% reduction in blood flow velocity to the brain, measured at the cerebral artery.
- Two-minute light-intensity walking breaks every 30 minutes: This frequency offset the decline and slightly boosted blood flow to the brain.
- Eight-minute light-intensity walking breaks every two hours: Longer, less frequent breaks failed to prevent the decline in blood flow.
The results, the authors concluded, “indicate that prolonged uninterrupted sitting in healthy desk workers reduces cerebral blood flow; however, this is offset when frequent short-duration walking breaks are incorporated”.
For anyone who engages in long periods of sedentary behavior, “chronically breaking up these sitting periods with frequent active break strategies may have important implications for cerebrovascular health,” they concluded.
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