Acute hypoxic injury caused by acute altitude exposure is manifested by different degrees of clinical symptoms, some of which may develop into acute mountain sickness (AMS). However, the current prevention and treatment methods are limited and there is a lack of safe and effective methods to prevent and reduce the severity.

To investigate the efficacy and safety of intermittent hypoxic (IH) training in preventing acute hypoxic injury by simulating hypoxic environment at an altitude of 4 400 meters.

A total of 40 subjects were recruited by public recruitment in Beijing Xiaotangshan Hospital from 2022-08-01 to 10-31 and randomly divided into the IH group (experimental group, n=20) and sham training group (control group, n=20). The experimental group received the IH exposure intervention with the total duration of 55 min twice a day for 5 d, including 10 min of low oxygen (oxygen concentration of 13%, simulated altitude of 3 800 m), 5 min of normoxia (oxygen concentration of 21%). The control group received the simultaneous long normoxia intervention. On the first day after the IH intervention training, the subjects entered into the simulated high-altitude hypoxia environment for 6 h, and the oxygen concentration was set at 12% (equivalent to the altitude of 4 400 m). The Lake Louise Scale (LLS) was used to assess the severity of AMS. Peripheral oxygen saturation (SpO₂), cerebral oxygen saturation (ScO₂) and intracranial pressure (ICP) were collected at baseline, before and 6 h after the simulated high-altitude hypoxia environment.

After 6 h of acute high-altitude hypoxia environment simulation, the incidence of AMS and LLS in the experimental group were significantly lower than those in the control group (P<0.05), SpO₂ in the experimental group was significantly higher than that in the control group (P<0.05). The results of intra-group comparison showed that SpO₂ and ScO₂ of subjects in both groups decreased significantly after 6 h of acute high-altitude hypoxia environment simulation compared with baseline and before acute high-altitude hypoxia environment simulation (P<0.05), the decrease level of SpO₂ after 6 h of acute high-altitude hypoxia environment simulation compared to before acute high-altitude hypoxia environment simulation in the experimental group was lower than the control group〔 (9.30±4.31 ) % vs. (13.10±6.66) %, P=0.039〕. The ICP was significantly increased after 6 h of acute high-altitude hypoxia environment simulation compared with before acute high-altitude hypoxia environment simulation in the control group (P<0.05) .

IH training can improve the to hypoxia tolerance of body, effectively reduce the incidence and severity of AMS.

急进高原会引起急性低氧损伤，出现不同程度的临床症状，有些可能发展成急性重症高原反应。然而目前防治方法有限，缺乏安全有效的预防及减轻其严重程度的方法。

通过模拟4 400 m海拔低氧环境，探讨间歇性低氧训练（IH）预防急性低氧损伤的有效性和安全性。

于2022-08-01—10-31在北京小汤山医院采用公开募集的方式招募受试者40名为研究对象，将受试者随机分为两组：IH组（试验组，n=20）和假训练组（对照组，n=20）。试验组接受10 min低氧（氧浓度13%，模拟海拔3 800 m）间隔5 min常氧（氧浓度21%），共4个循环，总持续时间为55 min的IH暴露干预，2次/d，连续干预5 d。对照组接受同时长的常压常氧干预。IH干预训练结束后的第1天，受试者进入模拟高原低氧环境6 h，设置氧浓度为12%（相当于海拔4 400 m）。采用路易斯湖评分（LLS）评估受试者急性高原病（AMS）的严重程度。收集受试者基线、急性高原低氧环境模拟前、急性高原低氧环境模拟6 h后外周血氧饱和度（SpO₂）、脑组织氧饱和度（ScO₂）和颅内压（ICP）。

急性高原低氧环境模拟6 h后，试验组AMS发生率及LLS总分低于对照组（P<0.05）。急性高原低氧环境模拟6 h后试验组SpO₂高于对照组（P<0.05）。组内比较结果显示，两组受试者在急性高原低氧环境模拟6 h后的SpO₂及ScO₂均较基线及急性高原低氧环境模拟前下降（P<0.05），试验组的急性高原低氧环境模拟6 h后较急性高原低氧环境模拟前SpO₂下降幅度小于对照组〔（9.30±4.31）%与（13.10±6.66）%，P=0.039〕。对照组急性高原低氧环境模拟6 h后ICP较急性高原低氧环境模拟前升高（P<0.05）。

IH训练可以提高机体的耐缺氧能力，有效降低急性高原反应发生率及严重程度。