de Sá Grace Barros, Rodrigues Gabriel Dias, Soares Pedro Paulo da Silva
Postgraduation Program in Cardiovascular Sciences, Fluminense Federal University, Niterói, Brazil.
Department of Clinical Sciences and Community Health, University of Milan, Milan, Italy.
Clin Physiol Funct Imaging. 2023 Jan;43(1):20-27. doi: 10.1111/cpf.12788. Epub 2022 Sep 29.
Fighter pilots (FP) are exposed to flight accelerations and stressful situations that defy cardiovascular control during and after flight. FP presents a smaller adjustment in sympatho-vagal balance during tilt test after flight compared to baseline, suggesting a huge impact of flight on autonomic modulation to the heart. We undertake to test the hypothesis that FP will have a smaller vagal reentrance and lower sympathetic withdrawal during the recovery at the supine position after a prolonged active standing test that mimics flight hemodynamic demands. Twenty-one military personnel (20-34 years old), composed of 9 FP and 12 non-pilots (NP) matched by age, V̉O and body mass index were enroled in the experimental protocol. R-R intervals were continuously recorded in the supine position for 15 min (SUP ), during the prolonged active standing test (45 min) windowed in six 5 min time frames (from ORT1 to ORT6), and a recovery period in the supine position for 15 min (SUP ). Heart rate variability was performed by spectral analysis to obtain the normalized low (LFn) and high (HFn) frequency components. The variation (Δ) from baseline (Δ = ORT6 - SUP ) and from recovery (Δ = SUP -ORT6) periods were calculated. FP had a smaller ΔLFn (sympathetic mediated) and ΔHFn (vagal meditated) during recovery after active standing as compared to NP. Both groups showed similar changes in ΔLFn and ΔHFn during orthostatic stress compared to baseline, with no differences over time. Therefore, FP show a smaller vagal reentrance and a lower sympathetic reduction during recovery at supine following active standing compared to NP.
战斗机飞行员（FP）在飞行期间和飞行后会面临飞行加速度和压力状况，这些会对心血管控制造成挑战。与基线相比，FP在飞行后的倾斜试验中交感-迷走神经平衡的调整较小，这表明飞行对心脏自主调节有巨大影响。我们试图检验这样一个假设：在模拟飞行血液动力学需求的长时间主动站立试验后，FP在仰卧位恢复过程中迷走神经再传入会更小，交感神经撤退会更低。21名军事人员（20 - 34岁）参与了实验方案，其中包括9名战斗机飞行员和12名年龄、静息耗氧量（V̇O₂）和体重指数相匹配的非飞行员（NP）。在仰卧位连续记录R - R间期15分钟（SUP），在长时间主动站立试验（45分钟）期间，划分为六个5分钟时间段（从ORT1到ORT6），之后再在仰卧位恢复15分钟（SUP）。通过频谱分析进行心率变异性分析，以获得标准化低频（LFn）和高频（HFn）成分。计算相对于基线（Δ = ORT6 - SUP）和恢复阶段（Δ = SUP - ORT6）的变化。与NP相比，FP在主动站立后的恢复过程中ΔLFn（交感神经介导）和ΔHFn（迷走神经介导）更小。与基线相比，两组在直立应激期间ΔLFn和ΔHFn的变化相似，且随时间无差异。因此，与NP相比，FP在主动站立后仰卧位恢复过程中迷走神经再传入更小，交感神经减少更低。
