Background: High-intensity interval exercise (HIIT) is currently being implemented in stroke rehabilitation to improve walking function. HIIT alternates between high-intensity and recovery bouts, which causes rapid increases and decreases in blood pressure, which may impact cerebrovascular function in people post-stroke. To date, there is no information on the acute cerebrovascular response in people post-stroke. To address this gap in knowledge, we tested whether the cerebrovascular response was reduced when compared to sedentary age- and sex-matched adults (CON) at the following timepoints: 1) baseline (BL), 2) during a single 10-minute bout of low-volume HIIT, 3) immediately following HIIT, and 4) 30 minutes after HIIT. Methods: Middle cerebral artery blood velocity (MCAv), mean arterial pressure (MAP), heart rate (HR), and end tidal carbon dioxide (PETCO2) were recorded at all timepoints. A submaximal exercise test was used to determine the estimated maximal workload. The low-volume HIIT bout was performed on a recumbent stepper and consisted of 1-minute high-intensity bouts (70% estimated maximal watts) separated by 1-minute active recovery (10% estimated maximal watts). Statistical analysis used linear mixed models and ANCOVA. Results: Individuals post-stroke demonstrated a reduced MCAv response during HIIT compared to CON (p = 0.03) and MCAv remained lower immediately following HIIT and 30-minutes after HIIT. MCAv decreased below BL immediately following HIIT in both groups (p ≤ 0.04) and returned to BL at 30-minutes after HIIT. No between differences were found for MAP, HR, and PETCO2. Conclusions: The key finding from this study suggests a reduced MCAv response during low-volume HIIT in individuals post-stroke compared to age and sex-matched sedentary adults and these differences remained up to 30 minutes following HIIT. Future work is needed to better understand the reduced MCAv response during HIIT despite increased metabolic demand. Clinicaltrials.gov #NCT04673994.
Fluctuating blood pressure during high-intensity interval exercise (HIIT) may challenge dynamic cerebral autoregulation (dCA), specifically post-stroke after an injury to the cerebrovasculature. We hypothesized dCA would be attenuated at rest and during a sit-to-stand, immediately following and 30 min after HIIT in individuals post-stroke compared to age- and sex-matched controls (CON). HIIT switched every minute between 70% and 10% estimated maximal watts for 10 min. Mean arterial pressure (MAP) and middle cerebral artery blood velocity (MCAv) were recorded. Resting dCA measured spontaneous fluctuations in MAP and MCAv via transfer function analysis. For sit-to-stand, time delay before an increase in cerebrovascular conductance index (CVCi = MCAv/MAP), rate of regulation, and %change in MCAv and MAP were measured. Twenty-two individuals post-stroke (age 60±12 yrs, 31±16 months) and twenty-four CON (age 60±13 yrs) completed the study. VLF gain (p=0.02, η2=0.18) and normalized gain (p=0.01, η2=0.43) had a group-by-time interaction, with CON improving immediately and 30 min after HIIT. Individuals post-stroke had impaired VLF phase (p=0.03, η2=0.22) immediately following HIIT compared to CON. We found no differences in the sit-to-stand. Our study showed lower resting dCA up to 30 min after HIIT in individuals post-stroke compared to CON while the sit-to-stand response was maintained.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.