Change in sleep, gastrointestinal symptoms, and mood states at high altitude (4500m) for 6 months.

PURPOSE

This study aimed to investigate the alterations in sleep quality and sleep patterns among military personnel at altitudes ranging from 1500 to 4500 m, as well as the associated factors influencing their sleep.

METHODS

This study employed a longitudinal prospective survey conducted over a period of six months, from November 2023 to June 2024. A total of 90 soldiers were recruited for participation. Initially, demographic data and sleep conditions were collected through a questionnaire administered to participants at an altitude of 1,500 m. Subsequently, participants were monitored continuously to gather data over seven days at an altitude of 4,500 m, specifically during the 7 days of the 6-month survey period), and the 1st month at an altitude of 4,500 m (on the 1st month of the six-month survey period. Spearman's rank correlation was utilized to investigate the relationships among sleep quality, gastrointestinal symptoms, and mood states.

RESULTS

The total score of the Pittsburgh Sleep Quality Index (PSQI) exhibited an increase, indicating impaired sleep quality among soldiers stationed at an altitude of 4,500 m for durations 7 days, 1 month, 3 months, and 6 months. Notably, after 7 days of soldiers, there was a significant gradual in the number of military soldiers experiencing gastrointestinal symptoms, such as diarrhea, abdominal distention, and constipation, which subsequently stabilized with prolonged exposure to the altitude. Furthermore, a significant rise in the incidence of depression was observed after days of rapid exposure 4,500 above sea level, and the emotional state of military personnel tended to tend towards mild depression over the duration of time Correlation. Correlation analysis showed that the PSQI score was closely related to the Athens Insomnia Scale(AIS) total score, Epworth Sleepiness Scale(ESS) total score, Self-Rating Anxiety Scale(SAS) total score, Self-Rating Depression Scale(SDS) total score, difficulty in falling asleep, easy to wake up or wake up early at night, poor breathing and snoring (on the 1st month, the 3rd month and the 6th month at the altitude of 4500 m respectively: rs = 0.868, 0.648, 0.483, 0.459, 0.472, 0.364, 0.613, 0.75; rs = 0.856, 0.521, 0.481, 0.354, 0.768, 0.720, 0.511, 0.535; rs = 0.756, 0.490, 0.496, 0.352, 0.708, 0.737, 0.424, 0.408, p < 0.01 or p < 0.05); Positively correlated with heart rate (at 4500 m 7 days at altitude: rs = 0.233, p = 0.027), diarrhea (at 4500 m 1-month at altitude: rs = 0.237) bloating and constipation (at 4500 m 1 month and 3months respectively: rs = 0.472; rs = 0.364; rs = 0.341, 0.273, p < 0.05); and with age, sex, marital status, education were significantly positive correlation (rs = 0.463, 0.251, 0.255, 0.230, p < 0.05).

CONCLUSIONS

The impaired sleep quality, gastrointestinal symptoms, and anxiety and depression in military personnel changed with the extension of the time of stationing at 4500 m altitude, which was most prominent when stationed at high altitude for 7 days; the sleep quality of those stationed at high altitude had a close relationship with the gastrointestinal symptoms, the type of sleep(insomnia and drowsiness), and the heart rate, but it varied with the duration of the stationing at high altitude; our study provides new information for the prevention of sleep disturbance, gastrointestinal symptoms, and negative emotions in high-altitude military personnel.