VR motion sickness, sometimes called simulator sickness, has a specific physiological cause that explains why it affects some users far more than others.
The core mechanism is a mismatch between what your eyes perceive as movement in the virtual environment and what your inner ear’s vestibular system senses about your body’s actual physical movement — when these two systems disagree significantly, nausea and disorientation commonly follow.
Experiences involving artificial movement without corresponding physical motion — being virtually moved through a space while physically stationary — tend to trigger this mismatch most strongly, while experiences matching virtual movement closely to actual physical movement tend to cause it far less.
Susceptibility varies significantly between individuals for reasons not fully understood, though building tolerance gradually with shorter sessions, and prioritizing experiences designed around physical movement rather than artificial locomotion, helps many susceptible users adapt over time.