Dynamic cerebral autoregulation is attenuated in young fit women

Labrecque, Lawrence; Rahimaly, Kevan; Imhoff, Sarah; Paquette, Myriam; Blanc, Olivier; Malenfant, Simon; Drapeau, Audrey; Smirl, Jonathan D; Bailey, Damian Miles; Brassard, Patrice

doi:10.14814/phy2.13984

Cited by 76 publications

(90 citation statements)

References 45 publications

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“…To evaluate the change in P ETCO 2 for each squatting frequency, the first and last five breaths were averaged. The difference between these two values represents the change in P ETCO 2 across that frequency as previously reported (Labrecque et al, 2019).…”

Section: Data Analysis 261 Baseline and P Etco 2 Datamentioning

confidence: 59%

“…The female cohort was also limited to three individuals in the sedentary group. Some authors report improved dCA in women compared to males (Favre & Serrador, ), whilst others report a reduction in dCA capacity in endurance‐trained females compared to age‐matched, endurance‐trained males (Labrecque et al., ). Abidi et al.…”

Section: Discussionmentioning

confidence: 99%

“…The female cohort was also limited to three individuals in the sedentary group. Some authors report improved dCA in women compared to males (Favre & Serrador, 2019), whilst others report a reduction in dCA capacity in endurance-trained females compared to age-matched, endurance-trained males (Labrecque et al, 2019). Abidi et al (2017) also suggested a modulatory role of ovarian hormones and oral contraceptives on cerebrovascular function to challenges such as standing and the Valsalva manoeuvre.…”

Section: Limitationsmentioning

confidence: 99%

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Implications of habitual endurance and resistance exercise for dynamic cerebral autoregulation

Perry

Cotter

Korad

et al. 2019

Experimental Physiology

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New Findings What is the central question of this study?Does habitual resistance and endurance exercise modify dynamic cerebral autoregulation? What is the main finding and its importance?To the authors’ knowledge, this is the first study to directly assess dynamic cerebral autoregulation in resistance‐trained individuals, and potential differences between exercise training modalities. Forced oscillations in blood pressure were induced by repeated squat–stands, from which dynamic cerebral autoregulation was assessed using transfer function analysis. These data indicate that dynamic cerebral autoregulatory function is largely unaffected by habitual exercise type, and further document the systemic circulatory effects of regular exercise. Abstract Regular endurance and resistance exercise produce differential but desirable physiological adaptations in both healthy and clinical populations. The chronic effect of these different exercise modalities on cerebral vessels’ ability to respond to rapid changes in blood pressure (BP) had not been examined. We examined dynamic cerebral autoregulation (dCA) in 12 resistance‐trained (mean ± SD, 25 ± 6 years), 12 endurance‐trained (28 ± 9 years) and 12 sedentary (26 ± 6 years) volunteers. The dCA was assessed using transfer function analysis of forced oscillations in BP vs. middle cerebral artery blood velocity (MCAv), induced via repeated squat–stands at 0.05 and 0.10 Hz. Resting BP and MCAv were similar between groups (interaction: both P ≥ 0.544). The partial pressure of end‐tidal carbon dioxide (P ETC O2) was unchanged (P = 0.561) across squat–stand manoeuvres (grouped mean for absolute change +0.6 ± 2.3 mmHg). Gain and normalized gain were similar between groups across all frequencies (both P ≥ 0.261). Phase showed a frequency‐specific effect between groups (P = 0.043), tending to be lower in resistance‐trained (0.63 ± 0.21 radians) than in endurance‐trained (0.90 ± 0.41, P = 0.052) and ‐untrained (0.85 ± 0.38, P = 0.081) groups at slower frequency (0.05 Hz) oscillations. Squat–stands induced mean arterial pressure perturbations differed between groups (interaction: P = 0.031), with greater changes in the resistance (P < 0.001) and endurance (P = 0.001) groups compared with the sedentary group at 0.05 Hz (56 ± 13 and 49 ± 11 vs. 35 ± 11 mmHg, respectively). The differences persisted at 0.1 Hz between resistance and sedentary groups (49 ± 12 vs. 33 ± 7 mmHg, P < 0.001). These results indicate that dCA remains largely unaltered by habitual endurance and resistance exercise with a trend for phase to be lower in the resistance exercise group at lower fequencies.

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Section: Data Analysis 261 Baseline and P Etco 2 Datamentioning

confidence: 59%

Section: Discussionmentioning

confidence: 99%

Section: Limitationsmentioning

confidence: 99%

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Implications of habitual endurance and resistance exercise for dynamic cerebral autoregulation

Perry

Cotter

Korad

et al. 2019

Experimental Physiology

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“…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.…”

Section: Discussionmentioning

confidence: 99%

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

et al. 2020

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Current protocols examining cerebral autoregulation (CA) parameters require participants to refrain from exercise for 12–24 hr, however there is sparse objective evidence examining the recovery trajectory of these measures following exercise across the cardiac cycle (diastole, mean, and systole). Therefore, this study sought to determine the duration acute exercise impacts CA and the within‐day reproducibility of these measures. Nine participants performed squat–stand maneuvers at 0.05 and 0.10 Hz at baseline before three interventions: 45‐min moderate‐continuous exercise (at 50% heart‐rate reserve), 30‐min high‐intensity intervals (ten, 1‐min at 85% heart‐rate reserve), and a control day (30‐min quiet rest). Squat–stands were repeated at hours zero, one, two, four, six, and eight after each condition. Transcranial doppler ultrasound of the middle cerebral artery (MCA) and the posterior cerebral artery (PCA) was used to characterize CA parameters across the cardiac cycle. At baseline, the systolic CA parameters were different than mean and diastolic components (ps < 0.015), however following both exercise protocols in both frequencies this disappeared until hour four within the MCA (ps > 0.079). In the PCA, phase values were affected only following high‐intensity intervals until hour four (ps > 0.055). Normalized gain in all cardiac cycle domains remained different following both exercise protocols (ps < 0.005) and across the control day (p < .050). All systolic differences returned by hour six across all measures (ps < 0.034). Future CA studies may use squat–stand maneuvers to assess the cerebral pressure–flow relationship 6 hr after exercise. Finally, CA measures under this paradigm appear to have negligible within‐day variation, allowing for reproducible interpretations to be drawn.

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“…An attenuated dynamic cerebral autoregulation (dCA), which describes the ability of the cerebrovasculature to respond to rapid changes in mean arterial pressure (MAP), in the posterior cerebral circulation could accentuate the reduction in blood supply to posterior regions of the brain following acute MAP reduction, which in turn could explain the appearance of symptoms in women during orthostatic stress. However, although we previously reported that healthy young fit women display diminished dCA in the MCA compared to men (Labrecque et al, 2019a), whether a differential dCA response between MCA and PCA in these young fit women remains to be clearly determined.…”

Section: Introductionmentioning

confidence: 79%

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

Labrecque

Drapeau

Rahimaly

et al. 2020

Preprint

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Individuals with low orthostatic tolerance show greater decrease in posterior cerebral artery mean blood velocity (PCAvmean). Since young fit women often experience presyncopal symptoms, their posterior cerebral circulation may be prone to greater decreases in PCAvmean, probably explained by an attenuated dynamic cerebral autoregulation (dCA). Regional differences in dCA have never been evaluated in young fit women. We compared dCA in the middle cerebral artery (MCA) and posterior cerebral artery (PCA) in 11 young fit women (25 ± 4y; ) in response to a sit-to-stand (5 min sitting followed by 5 min standing) and repeated squat-stand maneuvers performed at 0.05 Hz and 0.10 Hz. The cerebral pressure-flow relationship was characterized using four metrics: 1) percent reduction in blood velocity (BV) per percent reduction in MAP (% BV/% MAP) during initial orthostatic stress (0-15 s after sit-to-stand); 2) onset of the regulatory response (i.e. time delay before an increase in conductance (BV/MAP); 3) rate of regulation (RoR), following sit-to-stand and; 4) transfer function analysis (TFA) of forced MAP oscillations induced by repeated squat-stands. Upon standing, the relative decline in MCAvmean and PCAvmean was similar (−25 ± 9 vs. −30 ± 13%; p=0.29). The onset of the regulatory response (p=0.665), %ΔBV/%ΔMAP (p=0.129) and RoR (p=0.067) were not different between MCA and PCA. In regard to TFA, there was an ANOVA artery effect for gain (p<0.001) and a frequency effect for phase (p<0.001). These findings indicate the absence of regional differences in dCA in young fit women.New findingsWhat is the central question of this study?Are there regional differences in the dynamic cerebral autoregulation in young fit women?What is the main finding and its importance?The key finding of this study is that there are no differences in dynamic cerebral autoregulation between both arteries. These results indicate that dynamic cerebral autoregulation does not seem to be responsible for making the posterior cerebral circulation more vulnerable to transient reduction in blood pressure in young fit women.

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Dynamic cerebral autoregulation is attenuated in young fit women

Cited by 76 publications

References 45 publications

Implications of habitual endurance and resistance exercise for dynamic cerebral autoregulation

Implications of habitual endurance and resistance exercise for dynamic cerebral autoregulation

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

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

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