Larger reductions in BP during post-exercise standing, but not middle cerebral artery blood velocity, in resistance-trained vs untrained, 2024, Korad

Abstract
Dynamic resistance exercise (RE) produces sinusoidal fluctuations in blood pressure, with hypotension and cerebral hypoperfusion commonly observed immediately following RE. Whether the cerebral vasculature adapts to these regular blood pressure challenges is unclear.

This study examined the cerebrovascular response to post-dynamic RE orthostasis. RE-trained (n = 15, female = 4) and healthy untrained individuals (n = 15, female = 12) completed five stands: one after seated rest, with each of the subsequent four stands occurring immediately following a set of 10 repetitions of unilateral leg extension exercise at 60% of their one repetition maximum. Beat-to-beat blood pressure, mean middle cerebral artery blood velocity (MCAvmean) and end-tidal carbon dioxide were measured throughout.

During standing the mean arterial blood pressure (MAP) and MCAvmean nadirs were identified. There was no difference between groups for age (mean ± SD, 26 ± 7 RE-trained vs. 25 ± 6 years untrained, P = 0.683) or weight (78 ± 15 vs. 71 ± 15 kg, P = 0.683). At MAP nadir during the post-exercise stand, a greater reduction in MAP was observed in the RE-trained group (e.g., set 4, −45 ± 11 vs. −36 ± 6 mmHg, training effect P = 0.026).

However, post-exercise stand MCAvmean at MCAvmean nadir was not different (e.g., set 4, −20 ± 7 vs. −17 ± 6 cm/s, interaction effect P = 0.478). Rate of regulation was higher in the RE-trained group (set 1, 0.301 ± 0.170 vs. 0.167 ± 0.009, training effect P = 0.023).

Despite RE-trained individuals demonstrating greater absolute reductions in MAP during orthostasis following RE, there were no differences in MCAvmean, suggesting that habitual RE may mitigate post-exercise cerebral hypoperfusion.

Highlights

• What is the central question of this study?
  
  Resistance exercise produces vascular adaptations within the central arteries: does vascular adaptation also occur in the cerebral circulation?
  
  
• What is the main finding and its importance?
  
  Upon standing following moderate intensity dynamic resistance exercise, resistance-trained individuals demonstrated a greater decrease in mean arterial pressure compared to untrained individuals. However, the middle cerebral artery blood velocity response did not differ between groups, which may indicate more effective cerebral autoregulation during acute reduction in blood pressure initiated by orthostasis in the resistance-trained group.

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