Brand New Sentence

Just summarizing the literature.

Here's the full section:

The vestibular system doesn't operate in a hormonal vacuum. Estrogen receptors are present in the inner ear, and estrogen plays a role in regulating the fluid dynamics and blood flow in the vestibular apparatus. When estrogen is low — as it is in the days before menstruation, during pregnancy and lactation, and throughout perimenopause — vestibular function can become destabilized.

Research on motion sickness susceptibility across the menstrual cycle has found that susceptibility fluctuates with hormonal state, with this fluctuation accounting for roughly one-third of the overall difference between men and women in motion sickness rates. This isn't a trivial contributor.

Progesterone, which has a broadly calming effect on the nervous system, also drops during the luteal phase and perimenopause. Its reduction increases sensory reactivity and reduces resilience to stimuli that challenge the vestibular system — which is precisely what VR does.

This creates meaningful variability: the same woman using the same headset playing the same game may have very different responses depending on where she is in her cycle. It's one layer of the broader pattern that makes VR motion sickness worse on some days without any change in the VR experience itself.