Arterial and Intracranial Hypotension During and Following Exercise

Abstract

Exercise induced arterial hypertension and post-exercise arterial hypotension (PEH) are well-described phenomena with direct impact on cerebral blood flow. Cerebral perfusion pressure is given by the difference between mean arterial pressure at brain-level (MAPbrain) and intracranial pressure (ICP), however, little is known about effects of moderate aerobic exercise on ICP. We hypothesize that moderate exercise does not increase ICP thereby facilitating the augmented cerebral blood flow and that a post-exercise decrease in ICP is a contributing mechanism to maintained cerebral blood flow during PEH.Non-invasive (N=14) and invasive (N=3) ICP recordings and cardiovascular parameters were measured upright and supine before, during, and after 30 minutes of seated moderate aerobic bicycle exercise. Exercise elevated MAPbrain from 68±4 to 82±7 mmHg (mean±SEM, P<0.05) without elevating ICP, thus increasing CPP (72±3 to 87±6 mmHg, P<0.05). Compared to before exercise, we found significant PEH with a decrease in MAPbrain of 5±3% (5 mmHg; P<0.05), predominantly driven by a 26±5% (P<0.0001) decrease in total peripheral resistance (TPR). Because post-exercise ICP decreased concomitantly by 58±20% (P<0.0001) CPP remained unchanged. Recovery of ICP towards baseline was similarly correlated to TPR-recovery (R2=0.92, P<0.001), all variables returned to baseline within one hour.Here, we show for the first time ICP during and following aerobic exercise and consequences for cerebral perfusion. Periodic PEH is cardio-vascular protective and has long-term benefits for hypertensive patients, here we suggest that post-exercise decreases in ICP could similarly be cerebo-protective and in part explain the long-term beneficial effects of exercise for cerebral health and cognition. This work was supported by NASA grant no 80NSSC19K0020 and the Novo Nordic Foundation grant no NNF15OC0019196 This is the full abstract presented at the American Physiology Summit 2023 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.