Cerebrovascular Response to an Acute Bout of Short Interval High Intensity Interval Exercise and Recovery in Healthy Adults

IntroductionHigh intensity interval exercise (HIIE) is performed widely. However, the field possesses limited knowledge regarding the acute HIIE cerebrovascular response. Our objective was to characterize the middle cerebral artery blood velocity (MCAv) response during an acute bout of short interval HIIE in healthy adults. We hypothesized MCAv would decrease below BL 1) during HIIE, 2) following HIIE, 3) and 30-minutes after HIIE. As a secondary objective, we investigated sex differences in the MCAv response during HIIE. MethodsFourteen healthy adults (7 male) completed the HIIE session. The 10-minute HIIE session included alternating 1-minute bouts of high-intensity and low-intensity intervals. MCAv, mean arterial pressure (MAP), heart rate (HR), and expired end tidal carbon dioxide (PETCO2), were recorded at BL, during HIIE, following HIIE, and 30-minutes after HIIE. ResultsContrary to our hypothesis, MCAv remained above BL for the HIIE duration. MCAv peaked at the third minute then decreased concomitantly with PETCO2. MCAv was lower than BL after HIIE (p=0.03). Thirty minutes after HIIE, MCAv returned to near BL values (p = 0.47). Women showed higher BL MCAv ([Formula] = 70.9 {+/-} 8.1 cm{middle dot}s-1) compared to men ([Formula] = 59.3 {+/-} 5.8 cm{middle dot}s-1, p = 0.01). A greater magnitude of MCAv response was observed in men resulting in non-significant differences during HIIE secondary to higher workload (p = 0.03). ConclusionsCollectively, these findings show that in healthy adults, MCAv remained above BL during a 10-minute short-interval HIIE and returned to resting values 30 minutes after exercise.