Hypoxia and Ischemia Research Unit, School of Allied Health Sciences, Griffith University Gold Coast Campus, Parklands Drive, Parkwood, QLD, 4222, Australia.
Faculty of Sport Sciences, APERE Laboratory, EA 3300, University of Picardie Jules Verne, Amiens, France.
Eur J Appl Physiol. 2020 Mar;120(3):707-718. doi: 10.1007/s00421-020-04310-y. Epub 2020 Feb 14.
The purpose of this single-blind, repeated measures study was to investigate the effect of two hypoxic patterns, continuous or intermittent on key markers of haematological adaptation, stress and cardiac damage in healthy senior participants.
Fifteen healthy senior participants each followed a three-phase protocol over 3 consecutive weeks: (1) 5 consecutive days of breathing room air without a mask (2) 5 days of normoxic mask breathing (sham, FiO = 21%) (3) 5 days of intermittent hypoxia (IH) tailored to achieve a mean peripheral oxygen saturation (SpO) of 85% during ~ 70 min of cumulative exposure to hypoxia. After a 5-month washout period, participants were recalled to undertake continuous hypoxia (CH, SpO = 85%, ~ 70 min). The red blood cell count (RBC), haemoglobin concentration ([Hb]), haematocrit (Hct), percentage of reticulocytes (% Retics), secretory immunoglobulin A (S-IgA), cortisol, cardiac troponin T (cTnT) and the OFF-score (i.e. [Formula: see text]) were measured.
RBC only increased by day 5 of IH treatment compared to day 5 baseline values (+ 7.7%, p < 0.01) and day 5 Sham values (+ 12.9%, p < 0.01). [Hb] only increased by day 5 of IH treatment compared to day 5 baseline values (+ 14.7%, p < 0.01) and day 5 Sham values (+ 14.3%, p < 0.01). Hct (+ 12.7%, p < 0.01) and the OFF-score (p < 0.05) increased only during the final day of IH treatment. No difference was observed in S-IgA, cortisol or cTnT following IH or CH.
These results revealed that inherent differences in the IH and CH hypoxic patterns could provide crucial components required to trigger hematological changes in senior individuals, without eliciting immunological stress responses or damaging the myocardium.
本单盲、重复测量研究的目的是探讨两种低氧模式（连续或间歇）对健康老年参与者血液学适应、应激和心脏损伤关键标志物的影响。
15 名健康老年参与者在连续 3 周内遵循三阶段方案：（1）连续 5 天不戴面罩呼吸室内空气（2）连续 5 天在常压下戴面罩呼吸（假，FiO2=21%）（3）5 天间歇低氧（IH），旨在通过累积暴露于低氧约 70 分钟，使平均外周血氧饱和度（SpO2）达到 85%。在 5 个月的洗脱期后，参与者被召回进行连续低氧（CH，SpO2=85%，约 70 分钟）。测量红细胞计数（RBC）、血红蛋白浓度（[Hb]）、血细胞比容（Hct）、网织红细胞百分比（%Retic）、分泌型免疫球蛋白 A（S-IgA）、皮质醇、心肌肌钙蛋白 T（cTnT）和 OFF 评分（即 [Formula: see text]）。
仅在 IH 治疗的第 5 天，与第 5 天的基础值（+7.7%，p<0.01）和第 5 天 Sham 值（+12.9%，p<0.01）相比，RBC 才增加。[Hb]仅在 IH 治疗的第 5 天，与第 5 天的基础值（+14.7%，p<0.01）和第 5 天 Sham 值（+14.3%，p<0.01）相比，才增加。Hct（+12.7%，p<0.01）和 OFF 评分（p<0.05）仅在 IH 治疗的最后一天增加。在 IH 或 CH 后，S-IgA、皮质醇或 cTnT 没有差异。
这些结果表明，IH 和 CH 低氧模式的内在差异可能为触发老年个体血液学变化提供必要的组成部分，而不会引起免疫应激反应或损害心肌。
