Sex Differences in Post-exercise Hypotension, Ambulatory Blood Pressure Variability, and Endothelial Function After a Power Training Session in Older Adults

Background: The efficacy of power training (PT) to acutely reduce blood pressure (BP) in participants with hypertension is controversial, and no studies have assessed the influence of sex on post-exercise hypotension and its mechanisms in older adults.Purpose: The aims of this secondary, exploratory analysis were to compare the effects of a single bout of PT on post-exercise hypotension, BP variability, and endothelial function between older men and women with hypertension.Methods: Twenty-four participants with hypertension (12 men and 12 women aged to >60 years old) took part in this crossover study and randomly performed two experimental sessions: power exercise training (PT) and non-exercising control session (Con). The PT protocol was composed of 3 sets of 8–10 repetitions of five exercises performed in the following order: leg press, bench press, knee extension, upright row, and knee flexion, using an intensity corresponding to 50% of one repetition maximal test (1RM) and 2-min intervals between sets and exercises. The concentric phase of exercises during each repetition was performed “as fast as possible,” while the eccentric phase lasted 1 to 2 s. During Con, the participants remained at seated rest on the same exercise machines, but without any exercise. Each protocol lasted 40 min. Office BP, flow-mediated dilatation (FMD), 24-h ambulatory BP, and the average real variability (ARV) of systolic and diastolic BP were assessed before and after experimental sessions.Results: Comparing PT with Con, a reduced office BP after exercise was found in men (systolic BP—average post 1 h: −14 mmHg, p < 0.001; diastolic BP—average post 1 h: −8 mmHg, p < 0.001) and only a reduced systolic BP in women (average post 1 h: −7 mmHg, p = 0.04). Comparing men and women, a reduced systolic BP (post 60': −15 mmHg, p = 0.048; average post 1 h: −7 mmHg, p = 0.046) and diastolic BP (post 60': −9 mmHg, p = 0.049) after the first hour were found in men. In relation to 24-h ambulatory BP, ARV, and FMD, no statistically significant differences were found between men and women.Conclusion: In older adults with hypertension, the office BP response after the experimental sessions was different in men and women, showing that the PT protocol is more effective to acutely reduce BP in men. Additionally, the mechanisms behind this reduction remain unclear. This finding suggests that sex cannot be combined to analyze post-exercise hypotension.Clinical Trial Registration: ClinicalTrials.gov, Identifier: NCT03615625.

4 Histamine, mast cell tryptase and post-exercise hypotension in healthy and collapsed marathon runners

IntroductionHeat stress exacerbates post-exercise hypotension and cardiovascular disturbances from elevated body temperature and may contribute to exertion-related incapacity. Mast cell degranulation and muscle mass are considered likely modifiers, though this hypothesis lacks practical evidence. This study had three aims: 1) to characterise pre-post responses in histamine and mast cell tryptase (MCT); 2) to investigate relationships between whole body muscle mass (WBMM) and changes in blood pressure post marathon; 3) to identify any differences in runners incapacitated from marathon running.Methods24 recreational runners were recruited and successfully completed the 2019 Brighton Marathon (COMPLETION). WBMM was measured by bioimpedance at rested baseline. A further eight participants were recruited from incapacitated runners diagnosed with heat illness (COLLAPSE). Histamine, MCT, blood pressure, heart rate, body temperature and echocardiographic measures were taken before and after exercise (COMPLETION) and upon hyperthermic incapacitation (COLLAPSE).ResultsIn COMPLETION, MCT increased by nearly 50% from baseline (p=0.001), whereas histamine and body temperature did not vary (P>0.9462). Systolic (sBP), diastolic (dBP) and mean (MAP) arterial blood pressures and systemic vascular resistance (SVR) declined (p<0.019). WBMM negatively correlated with ΔsBP (r=-0.43, p=0.046). For COLLAPSE versus COMPLETION there were significant elevations in MCT (1769±244 ng/L vs 1179±431, p=0.001) and body temperature (39.8±1.3 vs 36.2±0.8°C, p<0.0001) with a non-significant rise in histamine (9.6±17.9μg/L vs 13.7±33.9, p=0.1074) and significantly lower MAP, dBP and SVR (p<0.0327).ConclusionsThese data support the hypothesis that mast cell degranulation is a vasodilatory mechanism underlying PEH and exercise associated collapse. The magnitude of PEH is inversely proportional to the muscle mass and enhanced by concomitant body heating.