Implications of habitual endurance and resistance exercise for dynamic cerebral autoregulation

Abstract

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.

The Acute Cardiorespiratory and Cerebrovascular Response to Resistance Exercise

“…As cerebrovascular compliance modulates cerebral autoregulation [141], it is plausible that repeated hypertensive stimuli may modify autoregulatory function. We have shown that despite the substantial differences between exercise types, aerobically trained individuals (excluding rowing) and resistance trained individuals demonstrate similar dynamic autoregulatory capacity during forced MAP oscillations (repeated squat stands) [142]. However, we did demonstrate a trend for transfer function derived gain to be greater during slower frequency (0.05 Hz) oscillations in MAP in the resistance trained cohort.…”

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.…”

Directional sensitivity of the cerebral pressure–flow relationship in young healthy individuals trained in endurance and resistance exercise

“…However, the greater blood flow pulsatility associated with a lower arterial compliance may affect the functional integrity of the brain (Palta et al., 2019) as well as cerebral microvascular function (Vikner et al., 2021). Despite these modality‐dependent cerebrovascular challenges, results from recent studies suggest no effect of exercise modality on dCA metrics derived from transfer function analysis (TFA) (Perry et al., 2019; Thomas et al., 2021). Following a 3‐month training programme of either endurance or resistance training, assessment of dCA using spontaneous oscillations revealed no impact of exercise modality (Thomas et al., 2021).…”

“…Thus, although quite debatable (Simpson & Claassen, 2018; Tzeng & Panerai, 2018), such MAP oscillations may be a preferable method when using TFA. However, a cross‐sectional study using driven MAP oscillations, forced by repeated squat–stands in young adults undertaking regular endurance and resistance exercise, showed no clear impact of habitual exercise modality on dCA (Perry et al., 2019). Therefore, training groups seem to have similar dCA.…”