Nice study that explains why sitting for long periods is so unhealthy - it reduces blood flow to the brain (cerebral blood flow) . The results from a study conducted in the United Kingdom (UK) found that prolonged, uninterrupted sitting (4 hours in the study) in healthy office workers reduced cerebral blood flow. However this was offset when frequent, short-duration walking breaks were taken - about 2 minutes of walking every 30 minutes. However, taking a 8 minute walking break every 2 hours did not have the same positive effect - even though that was the same amount of walking over the 4 hour period.
Maintaining good blood flow to the brain is a great reason to stretch your legs and walk a few minutes whenever possible, preferably at least every 30 minutes - whether at work or at home. From Medical Xpress:
Sitting for long hours found to reduce blood flow to the brain
A team of researchers with Liverpool John Moores University in the U.K. has found evidence of reduced blood flow to the brain in people who sit for long periods of time. In their paper published in the Journal of Applied Physiology, the group outlines the experiments they carried out with volunteers and what they found.
Suspecting that sitting for a long time could cause circulation problems to the brain, the researchers enlisted the assistance of 15 adult volunteers—each of them had a day job that required long hours of sitting. Each of the volunteers participated in three exercises over a period of time—each came to the lab on three separate occasions and sat for four hours. On each visit, they were fitted with a headband that measured blood flow to the brain using ultrasound. Each subject also wore a face mask that captured and measured carbon dioxide levels.
During the first exercise, the volunteers were asked to sit at a desk for four straight hours, leaving their chairs only to use the restroom. For the second exercise, each rose from their chair every 30 minutes and walked on a treadmill for two minutes. In the third exercise, each subject remained in their chair for two hours and then walked on the treadmill for eight minutes, then returned to the chair.
The researchers found evidence of reduced blood flow in all of the volunteers during all of the exercises. However, they also found that normal blood flow was restored by walking breaks. They report that the best outcome was when the volunteers took frequent two-minute walking breaks.
2 thoughts on “Sitting For Long Periods and Reduced Blood Flow To the Brain”
I haven't dived deep enough into the research to have a truly informed opinion, but I think we should be careful about deciding this is a health risk.
The article points out that reduced blood flow was "shown in the past to contribute to the likelihood of developing neurological disorders such as dementia." But we have no idea about the cause and effect here. It could be that aging processes lead to both reduced cerebral blood flow and dementia. Or that certain kinds of reduced blood flow are indicative of early dementia. Or that sitting only causes acute falls in blood flow, whereas chronic reduced blood flow is needed to contribute to dementia.
I totally agree, which is why I did not include those specific comments that were in the original research article. I just focused on the finding that reduced blood flow to the brain occurs from prolonged sitting and how one can reverse the effect - frequent 2 minute walks.