Sleep disturbances are the most common health issues in high-altitude environments. Current research on the sleep architecture of healthy populations is limited to the same altitude and involves a small number of subjects, lacking sufficient reliability.

This study aims to analyze the differences in sleep monitoring indicators among healthy adults of different ages and genders across various altitudes, exploring the impact of altitude, age, and gender interactions on these indicators.

Healthy volunteers recruited from the plains of Chengdu, Sichuan Province, and the plateau area of Kunming, Yunnan Province, from January 2020 to September 2022 were selected as study subjects. Volunteers' gender, height, body mass, Pittsburgh Sleep Quality Index (PSQI), and Epworth Sleepiness Scale (ESS) were collected. Total sleep time (TST), sleep efficiency, and sleep parameters [percentage of stage N1 (N1%), stage N2 (N2%), stage N3 (N3%) of non-rapid eye movement (NREM) sleep, and rapid eye movement (REM) sleep in total sleep time] were recorded. Age was categorized into two groups (20-39 and 40-60 years) for a two-way ANOVA to explore the effects of age, gender, and altitude on sleep parameters.

A total of 91 people were recruited in low-altitude areas, including 48 men and 43 women. A total of 90 people were recruited for the high-altitude area, including 46 men and 44 women. In females, TST was higher in high-altitude areas compared to low-altitude areas (P<0.05). In both males and females, N1% was higher and N2% was lower in high-altitude areas (P<0.05). N3% was higher in females than in males in high-altitude areas (P<0.05). In males, REM% was higher in high-altitude areas (P<0.05). TST was higher in the 20-39 age group than in the 40-60 age group in high-altitude areas (P<0.05). Sleep efficiency was higher in the 40-60 age group in low-altitude areas compared to high-altitude areas, with the 20-39 age group showing higher sleep efficiency in high-altitude areas (P<0.05). In both age groups, N1% was higher in high-altitude areas (P<0.05). In low-altitude areas, N1% was higher in the 20-39 age group than in the 40-60 age group, whereas in high-altitude areas, it was lower in the 20-39 age group (P<0.05). N2% was higher in low-altitude areas in both age groups (P<0.05), with the 40-60 age group having a higher N2% in high-altitude areas (P<0.05). N3% was higher in the 20-39 age group in high-altitude areas (P<0.05). In low-altitude areas, N3% was lower in the 20-39 age group compared to the 40-60 age group, while in high-altitude areas, it was higher in the 20-39 age group (P<0.05). REM% was higher in high-altitude areas in both age groups (P<0.05) .

The factors of age and altitude have varying degrees of influence on total sleep time, sleep efficiency, N1%, N2%, and REM%. Age factors have a greater impact on sleep structure, the older the age, the shorter TST, the lower the sleep efficiency, the higher the proportion of N1. The higher the altitude, the greater the influence of age on sleep structure. In the high altitude area, the TST, sleep efficiency and N3% of the elderly population are lower, and the proportion of N1% is higher.