Consistency of hemodynamic and autonomic mechanisms underlying post-exercise hypotension

Abstract

Post-exercise hypotension (PEH) is a clinically relevant phenomenon, but its mechanisms vary between different studies and between the participants within each study. Additionally, it is possible that PEH mechanisms are not consistent in each individual (i.e. within-individual variation), which has not been investigated yet. Thus, the aim of the current study was to assess the within-individual consistency of PEH hemodynamic and autonomic mechanisms. For that, 30 subjects performed 4 sessions divided in 2 blocks (test and retest). In each block, an exercise (cycling, 45min, 50%VO 2 peak) and a control (seated rest, 45min) session was randomly conducted. Blood pressure (BP) and its mechanisms were evaluated pre and post-interventions. In each block, individual responses were calculated as post-exercise minus post-control, and a response was considered present when its magnitude reached the typical error of the measurement. Consistencies were evaluated by comparing test and retest responses through kappa coefficient (k). PEH consistency was calculated using role sample, while mechanisms consistency was evaluated in those with consistent PEH. Twenty-one (70%) participants showed consistent PEH, 5 (17%) presented PEH in only test or retest and 4 (13%) had absent PEH response, characterizing a good consistency (k= 0.510). Regarding mechanisms' responses, good consistency was found for heart rate (k=0.456), sympathovagal balance (k=0.438) and baroreflex sensitivity (k=0.458); while systemic vascular resistance (k=0.152), cardiac output (k=-0.400), stroke volume (k=-0.055) and sympathetic vasomotor modulation (k=-0.096) presented marginal consistencies. Thus, PEH is a highly consistent physiological phenomenon, although its mechanisms present variable consistencies.

Effect of Exercise Prior to Sedentary Behavior on Vascular Health Parameters: A Systematic Review and Meta-Analysis of Crossover Trials

“…Regarding vascular function parameters, four studies reported results of prior exercise on FMD [ 30 , 32 , 37 , 47 ] four on SR [ 30 , 32 , 37 , 47 ], and two on BF [ 31 , 32 ]. Regarding central hemodynamic parameters, six studies reported results on HR [ 38 , 48 – 52 ], and ten studies on BP [ 30 , 32 , 37 , 38 , 48 – 53 ].…”

“…Four articles provided data on vascular function variables, with three studies contributing data on the effects on FMD [ 30 , 32 , 37 ] and SR [ 30 , 32 , 37 ], and two studies on BF [ 31 , 32 ]. For hemodynamic parameters, data from six articles were used, with three studies examining the effects on HR [ 38 , 48 , 51 ] and five studies on BP [ 30 , 32 , 37 , 38 , 51 ]. All studies employed a randomized crossover controlled trial design, with sample sizes ranging from 10 [ 31 , 37 , 52 ] to 67 individuals [ 49 ].…”

“…The studies used experimental intervention strategies based on prior exercise to SB through different modalities such as: cycling on a cycle ergometer at a light-intensity [ 48 ], moderate-intensity strategies such as walking on a treadmill [ 30 , 38 , 49 , 50 ] or cycling [ 32 , 37 , 51 , 52 ], and high-intensity strategies practiced in an interval modality [ 31 , 37 , 47 , 53 ]. These interventions involved prior exercise application lasting between 10 [ 38 ] and 45 min [ 30 , 32 , 48 ]. The characteristics of the included studies and intervention details are presented in Table 1 .…”

“…FMD 3h (third hour): no effect of any intervention compared to control trial. SR AUC : no effect of any intervention compared to control trial at 1–3 h BP : no effect of any intervention compared to control trial 1–3 h Fecchio et al [ 48 ] Randomized cross-over trial 30 6 women 24 men 42 ± 11 30.1 ± 5.1 N/E BP was assessed with an auscultatory technique in the dominant arm and a mercury sphygmomanometer. Electrocardiography was used for HR.…”

“…Regarding the studies that assessed the effect of prior exercise on BP during exposure to SB, three of them showed a reduction in mean BP [ 38 , 48 , 49 ] and seven reported no effect [ 30 , 32 , 37 , 50 – 53 ]. The analysis of BP considered the mean arterial pressure obtained in the included studies during the experimental intervention (prior exercise to prolonged SB) and the control condition (prolonged SB without prior exercise).…”