Sex differences in visual performance and postural sway precede sex differences in visually induced motion sickness.

Motion sickness is more common among women than among men. Previous research has shown that standing body sway differs between women and men. In addition, research has shown that postural sway differs between individuals who experience visually induced motion sickness and those who do not and that those differences exist before exposure to visual motion stimuli. We asked whether sex differences in postural sway would be related to sex differences in the incidence of visually induced motion sickness. We measured unperturbed standing body sway before participants were exposed to visual motion stimuli that induced motion sickness in some participants. During postural testing, participants performed different visual tasks. Results revealed that postural sway was affected by visual tasks, consistent with the literature. In addition, we found a statistically significant three-way interaction between visual tasks, sex, and (subsequent) motion sickness status. These results suggest that sex differences in motion sickness may be related to sex differences in the control of postural balance.