Sleep's influence on susceptibility to motion sickness in parabolic flights and virtual reality: An exploratory study

ObjectivesThe relationship between sleep and motion sickness (MS) remains underexplored. This study examined whether objective sleep parameters were related to susceptibility to motion sickness, elicited by different sensory conflicts.MethodsIn a cross-over design, twenty-six participants completed a virtual reality (VR) paradigm inducing cybersickness-provoking stimuli, while twenty of them underwent a parabolic flight (PF) simulating space sickness. Actigraphy was recorded during a period of 6 nights for each paradigm to measure objective sleep quality, while subjective sleep ratings, motion sickness scores, nausea onset, and cortisol levels were collected throughout the experiment.ResultsBetter sleep quality before the paradigm-reflected by greater sleep efficiency, shorter sleep onset latency, less wake after sleep onset, and longer total sleep time-was associated with lower motion sickness severity during PF, but not with lower cybersickness in VR. Stress, whether subjective or cortisol-based, did not correlate with motion sickness levels in PF.ConclusionsOur findings show that sleep quality may protect against motion sickness in parabolic flights, independent of stress, even in those without sleep disorders. These findings identify sleep metrics as possible predictors of susceptibility to altered-gravity motion sickness.