Relationship between sleep quality and gravitational Tolerance.

ABSTRACT

BACKGROUND: The purpose of this study was to investigate the relationship between sleep quality and gravitational tolerance because sleep could directly affect physiological variables of the human body. METHODS: For the present study, 157 male Korea Air Force Academy cadets were recruited. They were assigned into a gravity (G)-tolerance test pass group (GP, n = 87) and a G-tolerance test fail group (GF, n = 70). All participants were assessed for G-tolerance test and Pittsburgh Sleep Quality Index (PSQI), a self-report questionnaire. Physical fitness test was performed based on the physical fitness test of the Ministry of National Defense of Korea. RESULTS: Independent t-test showed that PSQI global score (p < 0.001), PSQI sleep quality (p < 0.001), PSQI sleep onset latency (p = 0.009), PSQI sleep disturbance (p < 0.001), and PSQI daytime dysfunction (p < 0.001) were significantly different between the two groups. Participants with PSQI score less than 5 were more likely to have a longer G-tolerance test time (OR = 4.705, 95% CI = 2.00-11.05). Additionally, associations between those with PSQI score less than 5 (OR = 4.567, 95% CI = 1.94-10.74) were after adjusting (< 30 s and ≥ 30 s) for covariates. A negative correlation was found between G-tolerance test time and PSQI global score (p < 0.001). Negative correlations were found among 3 km running, push-up (p < 0.001), and sit-up (p < 0.001). A positive correlation was found between push-up and sit-up (p < 0.001). CONCLUSION: In conclusion, participants with good sleep quality were 4.705 times more likely to have longer G-tolerance test time. Thus, it is important for aircraft pilots to manage their sleep quality. Pre-pilots should also improve their sleep quality to pass the G-tolerance test.