Six weeks of high‐intensity interval training to exhaustion attenuates dynamic cerebral autoregulation without influencing resting cerebral blood velocity in young fit men

Abstract

Elevated cardiorespiratory fitness (CRF) is associated with reduced dynamic cerebral autoregulation (dCA), but the impact of exercise training per se on dCA remains equivocal. In addition, resting cerebral blood flow (CBF) and dCA after high‐intensity interval training (HIIT) in individuals with already high CRF remains unknown. We examined to what extent 6 weeks of HIIT affect resting CBF and dCA in cardiorespiratory fit men and explored if potential changes are intensity‐dependent. Endurance‐trained men were assigned to group HIIT 85 (85% of maximal aerobic power, 1–7 min effort bouts, n = 8) and HIIT 115 (115% of maximal aerobic power, 30 sec to 1 min effort bouts, n = 9). Training sessions were completed until exhaustion 3 times/week over 6 weeks. Mean arterial pressure (MAP) and middle cerebral artery mean blood velocity (MCAv mean ) were measured continuously at rest and during repeated squat‐stands (0.05 and 0.10 Hz). Transfer function analysis (TFA) was used to characterize dCA on driven blood pressure oscillations during repeated squat‐stands. Neither training nor intensity had an effect on resting MAP and MCAv mean (both P > 0.05). TFA phase during 0.10 Hz squat‐stands decreased after HIIT irrespective of intensity (HIIT 85 : 0.77 ± 0.22 vs. 0.67 ± 0.18 radians; HIIT 115 : pre: 0.62 ± 0.19 vs. post: 0.59 ± 0.13 radians, time effect P = 0.048). These results suggest that HIIT over 6 weeks have no apparent benefits on resting CBF, but a subtle attenuation in dCA is seen posttraining irrespective of intensity training in endurance‐trained men.

Dynamic cerebral autoregulation across the cardiac cycle during 8 hr of recovery from acute exercise

“…Furthermore, the modality of exercise performed by individuals has appreciable effects on the cerebral pressure‐flow response. As such, future investigations will need to also consider the modality of exercise performed and potentially the sporting background (Perry et al, ) of subjects as the potential long‐term exposure to MICT and/or HIIT patterns may differentially alter cerebral autoregulatory capacity (Drapeau et al, ; Labrecque et al, ; Lind‐Holst et al, ). Taken together, the results from this investigation demonstrate that refraining from exercise for 12–24 hr prior to dynamic CA data collection is excessively conservative.…”

Effects of high intensity interval exercise on cerebrovascular function: A systematic review

“…Cerebrovascular reactivity is a measure of cerebrovascular regulation [ 56 ] and shows the ability of the vessels to vasodilate or vasoconstrict to a stimulus [ 57 ]. Cerebrovascular conductance index is a measure of the conductance of peripheral blood pressure to cerebral blood velocity and is calculated as MCAv/mean arterial pressure (MAP) [ 45 ]. Cerebrovascular resistance index (MAP/MCAv) measures the resistance of cerebral perfusion pressure to cerebral blood velocity [ 45 ].…”

“…Cerebrovascular conductance index is a measure of the conductance of peripheral blood pressure to cerebral blood velocity and is calculated as MCAv/mean arterial pressure (MAP) [ 45 ]. Cerebrovascular resistance index (MAP/MCAv) measures the resistance of cerebral perfusion pressure to cerebral blood velocity [ 45 ].…”

Multi-metrics assessment of dynamic cerebral autoregulation in middle and posterior cerebral arteries in young fit women

“…Vc O2max was determined during a progressive ramp exercise protocol performed on an electromagnetically braked upright cycle ergometer (Corival, Lode, the Netherlands) to characterize cardiorespiratory fitness of the participants as previously described (Drapeau et al, 2019;Labrecque et al, 2017;.…”

“…Following a minimum of 10 min in a standing quiet rest to ensure stabilization of baseline haemodynamics following the sit-to-stand maneuver, repeated squat-stands were performed as previously described (Drapeau et al, 2019;Labrecque et al, 2019a). Briefly, participants were asked to alternate standing and squatting positions during 5 min at frequencies of 0.05 Hz (10-s squat, 10-s standing) and 0.10 Hz (5-s squat, 5-s standing).…”