Faculty of Sport, University of Ljubljana, Ljubljana, Slovenia.
Department of Automation, Biocybernetics, and Robotics, Jozef Stefan Institute, Ljubljana, Slovenia.
Eur J Appl Physiol. 2020 Jun;120(6):1341-1355. doi: 10.1007/s00421-020-04366-w. Epub 2020 Apr 8.
We compared the effects of hypobaric and normobaric hypoxia on select cardio-respiratory responses, oxidative stress and acute mountain sickness (AMS) severity in prematurely born individuals, known to exhibit blunted hypoxic ventilatory response.
Sixteen prematurely born but otherwise healthy males underwent two 8-h hypoxic exposures under: (1) hypobaric hypoxic [HH; terrestrial altitude 3840 m; PO:90.2 (0.5) mmHg; BP: 478 (2) mmHg] and (2) normobaric hypoxic [NH; PO:90.6 (0.9) mmHg; FO:0.142 (0.001)] condition. Resting values of capillary oxyhemoglobin saturation (SpO), heart rate (HR) and blood pressure were measured before and every 2 h during the exposures. Ventilatory responses and middle cerebral artery blood flow velocity (MCAv) were assessed at rest and during submaximal cycling before and at 4 and 8 h. Plasmatic levels of selected oxidative stress and antioxidant markers and AMS symptoms were also determined at these time points.
HH resulted in significantly lower resting (P = 0.010) and exercise (P = 0.004) SpO as compared to NH with no significant differences in the ventilatory parameters, HR or blood pressure. No significant differences between conditions were found in resting or exercising MCAv and measured oxidative stress markers. Significantly lower values of ferric-reducing antioxidant power (P = 0.037) were observed during HH as opposed to NH. AMS severity was higher at 8 h compared to baseline (P = 0.002) with no significant differences between conditions.
These data suggest that, in prematurely born adults, 8-h exposure to hypobaric, as opposed to normobaric hypoxia, provokes greater reductions in systemic oxygenation and antioxidant capacity. Further studies investigating prolonged hypobaric exposures in this population are warranted.
NCT02780908 (ClinicalTrials.gov).
我们比较了低压缺氧和常压缺氧对选择性心肺反应、氧化应激和急性高原病（AMS）严重程度的影响，这些人出生过早，已知其缺氧通气反应迟钝。
16 名早产但其他方面健康的男性在以下两种情况下接受了两次 8 小时的缺氧暴露：（1）低压缺氧[HH；海拔 3840 米；PO：90.2（0.5）mmHg；BP：478（2）mmHg]和（2）常压缺氧[NH；PO：90.6（0.9）mmHg；FO：0.142（0.001）]。在暴露前和暴露期间每 2 小时测量毛细血管血氧饱和度（SpO）、心率（HR）和血压的静息值。在暴露前和 4 小时和 8 小时时，评估休息时和次最大循环时的通气反应和大脑中动脉血流速度（MCAv）。还在这些时间点测定了选定的氧化应激和抗氧化标志物以及 AMS 症状的血浆水平。
HH 导致静息（P=0.010）和运动（P=0.004）时的 SpO 明显低于 NH，而通气参数、HR 或血压无明显差异。在静息或运动时的 MCAv 和测量的氧化应激标志物方面，两种条件之间没有发现显著差异。HH 时的铁还原抗氧化能力（P=0.037）明显低于 NH。与基线相比，8 小时时 AMS 严重程度更高（P=0.002），但两种条件之间无显著差异。
这些数据表明，在早产成年人中，与常压缺氧相比，8 小时的低压缺氧暴露会导致全身氧合和抗氧化能力的更大降低。在该人群中进行长期低压暴露的进一步研究是必要的。
NCT02780908（ClinicalTrials.gov）。
