Earth Vertical Motions Disrupt Sleep and Next Day Performance

Overcoming travel-related sleep disturbances due to motions sensed by our vestibular system could help improve cognitive performance and sleep quality in many contexts. However, there is a lack of research that administers controlled motions to understand how motion negatively impacts sleep and cognitive performance.

In this experiment, nine participants (21-39 years, M = 30.3, SD = 6.76; 3 females) completed a 7-day protocol. During nights 1-3, participants wore an Actiwatch and completed sleep diaries at home. On nights 4-7, participants slept in the lab with polysomnographic recording equipment on a bed attached to a movement platform and completed a psychomotor vigilance test at 07:00AM, 1:00PM, 3:00PM, and 5:00PM. On nights 4 and 5, the bed did not move overnight. On nights 6 and 7, the bed was moved upward and downward at 1Hz up to 120 times overnight at levels between 0-100% and 0-600% of each participant's awake perceptual vertical motion threshold, respectively.

Vertical motions significantly increased arousals from sleep (p =0.014) and worsened morning and midday psychomotor vigilance (p <0.001). Arousals caused by vertical motions occurred less than natural arousals (p <0.001) and had different spectral power (p =0.002). Larger motions strongly and significantly predicted a higher chance of causing arousals (β =0.0016, p <0.001).

These results provide evidence that overnight vertical motions disrupt sleep, lead to arousals that are distinct from natural arousals, and result in decreased cognitive performance. Strategies to reduce motion could help mitigate travel-related sleep disturbances.