Prolonged sitting might not harm oxygen levels in the brain in young adults

Though prolonged sitting is associated with a variety of consequences, it may not impair the body’s ability to deliver oxygen to the brain in healthy adults, according to new preliminary research from the University of North Carolina at Chapel Hill.

“The UNC Cardiometabolic Lab has a particular interest in understanding the mechanisms by which repeated exposure to prolonged sitting leads to chronic cardiovascular complications. And by ‘cardiovascular’ we have to remember that this includes cerebrovascular,” said study author Lee Stoner, an assistant professor of exercise physiology.

“We were originally interested on the effects of prolonged sitting on heart health, and a natural extension was the brain. This is particularly important when considering the epidemiological evidence associating sedentary behaviors with dementia risk factors.”

“Further, cerebrovascular complications likely contribute to dementia, and there’s a clear need to identify strategies to offset dementia risk in the aging population,” Stoner explained.

The researchers used near‐infrared spectroscopy to monitor perfusion — or penetration of blood into tissue — in the prefrontal cortex in 20 healthy participants as they sat for three hours. However, this continuous sitting did not lead to impairments in prefrontal cortex oxygen delivery.

“Contrary to expected, we found the prolonged sitting did not decrease cerebral perfusion or executive function. Further, simple exercises such as calf raises during prolonged sitting may not be of benefit to the cerebral perfusion or executive function in healthy young adults,” Stoner explained.

But additional research using at-risk populations — such as older adults and those with chronic disease — should be conducted.

“This initial study investigated healthy, young adults. We do not know whether our findings extend to older and/or unhealthy adults. The executive function test we used, Stroop test, may not be the most sensitive for use in young adults,” Stoner said.

“We measured cerebral perfusion but not cerebral blood flow. Cerebral blood flow may have been compromised (as shown by another study), but the brain worked over time to regulate perfusion.”

The study, “Effects of acute prolonged sitting on cerebral perfusion and executive function in young adults: A randomized cross‐over trial“, was authored by Lee Stoner, Quentin Willey, William S. Evans, Kathryn Burnet, Daniel P. Credeur, Simon Fryer, and Erik D. Hanson.