Chronic And Acute Benefits Of Reduced Sitting In Individuals With Increased Cardiovascular Risk

The influence of sex and maturation on carotid and vertebral artery hemodynamics and associations with free-living (in)activity in 6–17-year-olds

“…Habitual sedentary time has been associated with lower cerebral blood flow (CBF) to the lateral and medial frontal cortex, but not the medial temporal cortex in older adults (9). Conversely, when total sedentary time was reduced over a 16-week period, an increase in intra-cranial blood velocity of the anterior circulation was noted in older adults (10). It is well-established that it is the manner in which sitting is accumulated that impacts health, with prolonged, uninterrupted bouts of sitting the most detrimental (11), including to the cerebrovasculature.…”

“…It is well-established that it is the manner in which sitting is accumulated that impacts health, with prolonged, uninterrupted bouts of sitting the most detrimental (11), including to the cerebrovasculature. Evidence from the acute manipulation of sitting in adults has shown reductions in CBF velocity following three hours of uninterrupted sitting, again in the anterior cerebral circulation, with reductions that were countered by shortening the bout of prolonged sitting with activity breaks (10,12). Although the negative impact of prolonged uninterrupted sitting on CBF in adults is becoming clearer, whether there are regional differences remains undetermined.…”

“…In adults, there is evidence of a shear-mediated dilation of the internal carotid artery (ICA) in response to various stimuli including exercise, hypercapnia, and intermittent hypoxia (14-18). It is possible that the noted reductions in anterior CBF with excessive sitting (9,10,12) result in a concomitant reduction in arterial wall shear-stress, but this has yet to be described.…”