Rehabilitation and Exercise Science Laboratory (RES lab), Department of Business Economics, Health and Social Care, University of Applied Sciences and Arts of Southern Switzerland, Landquart, Switzerland.
International University of Applied Sciences THIM, Landquart, Switzerland.
PLoS One. 2022 Nov 10;17(11):e0277364. doi: 10.1371/journal.pone.0277364. eCollection 2022.
This partially randomised controlled, crossover study sought to investigate the effects of normobaric hypoxia (NH) and hypobaric hypoxia (HH) on cognitive performance, the physiological response at rest and after a 3-min step-test. Twenty healthy participants (10 females and 10 males, 27.6±6.2yrs, 73.6±13.7kg, 175.3±8.9cm) completed a cognitive performance test, followed by the modified Harvard-step protocol, in four environments: normobaric normoxia (NN; PiO2: 146.0±1.5mmHg), NH (PiO2: 100.9±1.3mmHg), HH at the first day of ascent (HH1: PiO2 = 105.6±0.4mmHg) and HH after an overnight stay (HH2: PiO2 = 106.0±0.5mmHg). At rest and/or exercise, SpO2, NIRS, and cardiovascular and perceptual data were collected. The cerebral tissue oxygenation index and the cognitive performance (throughput, accuracy, and reaction time) were not different between the hypoxic conditions (all p>0.05). In NH, SpO2 was higher compared to HH1 (ΔSpO2 NH vs HH1: 1.7±0.5%, p = 0.003) whilst heart rate (ΔHR NH vs HH2: 5.8±2.6 bpm, p = 0.03) and sympathetic activation (ΔSNSi NH vs HH2: 0.8±0.4, p = 0.03) were lower in NH compared to HH2. Heart rate (ΔHR HH1 vs HH2: 6.9±2.6 bpm, p = 0.01) and sympathetic action (ΔSNSi HH1 vs HH2: 0.9±0.4, p = 0.02) were both lower in HH1 compared to HH2. In conclusion, cognitive performance and cerebral oxygenation didn't differ between the hypoxic conditions. SpO2 was only higher in NH compared to HH1. In HH2, heart rate and sympathetic activation were higher compared to both NH and HH1. These conclusions account for a PiO2 between 100-106 mmHg.
本部分随机对照交叉研究旨在探讨常压低氧（NH）和低海拔低氧（HH）对认知表现、静息和 3 分钟台阶测试后生理反应的影响。20 名健康参与者（10 名女性和 10 名男性，27.6±6.2 岁，73.6±13.7kg，175.3±8.9cm）完成了认知表现测试，随后进行了改良哈佛台阶方案，在四种环境下进行：常压常氧（NN；PiO2：146.0±1.5mmHg）、NH（PiO2：100.9±1.3mmHg）、第一天上升时的 HH1（PiO2=105.6±0.4mmHg）和过夜后 HH2（PiO2=106.0±0.5mmHg）。在休息和/或运动时，收集 SpO2、NIRS、心血管和感知数据。在缺氧条件下，脑组织氧合指数和认知表现（吞吐量、准确性和反应时间）没有差异（所有 p>0.05）。在 NH 中，SpO2 高于 HH1（ΔSpO2 NH vs HH1：1.7±0.5%，p=0.003），而心率（ΔHR NH vs HH2：5.8±2.6bpm，p=0.03）和交感神经激活（ΔSNSi NH vs HH2：0.8±0.4，p=0.03）在 NH 中低于 HH2。与 HH2 相比，心率（ΔHR HH1 vs HH2：6.9±2.6bpm，p=0.01）和交感神经作用（ΔSNSi HH1 vs HH2：0.9±0.4，p=0.02）在 HH1 中均较低。总之，认知表现和脑氧合在缺氧条件下没有差异。与 HH1 相比，NH 中的 SpO2 仅较高。在 HH2 中，与 NH 和 HH1 相比，心率和交感神经激活更高。这些结论适用于 100-106mmHg 的 PiO2。
