Effects of aircraft noise on sleep quality in daytime vs. nighttime sleep

Kurzfassung

Objective This study examines the effects of the timing of the sleep (nighttime vs. daytime) and aircraft noise exposure on sleep quality. Background Fragile daytime sleep occurs due to abnormal circadian rhythm. In addition, daytime sleepers are exposed to higher environmental noise than nighttime sleepers. Transportation noise is a main cause for sleep disturbances and can have short-term as well as long-term effects. Method This study was conducted in a laboratory with subjects (N = 33, 18 females, aged 18 to 40 years) being exposed to artificial aircraft sounds of several aircraft types. Subjects slept either during the day or at night, twice with noise exposure and twice without noise exposure. The linear mixed model (LMM) with random intercept with repeated measurements was used to assess the sleep quality based on total sleep time (TST), sleep efficiency (SE), Waketime after sleep onset (WASO), Sleep stages 1-2, SWS, REMS, number of awakenings (AWR) and number of changes from slow wave sleep (SWSchange) to S2 or REMS. Results Sleep quality differed significantly between daytime and nighttime sleep as well as between sleep episodes with noise and without noise but not throughout all analyses. There was a significant interaction between timing of sleep and noise exposure on S1. Sleep quality differed between the first and the second sleep episode. Moreover, the effects of the timing of sleep and noise exposure, respectively, differed between the first and the second sleep episode, although these interactions were not significant throughout all analyses. Conclusion Both, daytime sleep and noise exposure have a negative impact on sleep quality. Moreover, there is the potential for a synergetic effect between noise exposure and the time of sleep, indicating a higher impact of noise exposure on sleep quality for sleep during daytime. Differences in sleep quality between the first and the second sleep episode point at carry-over effects of both the noise exposure and the timing of sleep.