A controlled comparative study on the effect of arterial occlusion pressure on immediate sympathetic and hyperemic responses

Different levels of arterial occlusion pressure (AOP) can influence microcirculatory responses and autonomic nervous system activity, potentially affecting individuals undergoing training methods that incorporate AOP, such as blood flow restriction (BFR) training. Therefore, this study aimed to compare the effects of four distinct AOP levels on microcirculatory responses and autonomic nervous system activity-specifically investigating the relationship between post-occlusive reactive hyperemia (PORH), hemodynamic parameters, and heart rate variability (HRV) metrics. This prospective experimental study involved 30 healthy adults who underwent standardized assessments of heart rate variability (HRV) and post-occlusive reactive hyperemia (PORH) across four arterial occlusion pressure (AOP) levels (40, 80, 100, 130%). Measurements were conducted under controlled environmental conditions and consistent body positioning, enabling an analysis of microcirculatory and autonomic responses under progressive vascular occlusion. The results showed no significant changes in resting flow across AOP levels (p = 0.847), while all other parameters-biological zero, peak hyperemia, time to peak, average NN interval, standard deviation of NN intervals, and heart rate-exhibited significant differences between AOP conditions (all p < 0.001, except low frequency to high frequency ratio p < 0.05). However, for most variables, no significant differences were observed between 100 and 130% AOP (p > 0.999), indicating a possible stabilization of physiological responses at higher occlusion pressures. This study concludes that while increasing arterial occlusion pressure significantly affects multiple physiological parameters, responses tend to stabilize between 100 and 130% AOP, suggesting a threshold beyond which further increases yield minimal additional physiological impact.Trial registration trial number ISRCTN15418049.