Why does motion sickness happen to me?
Although VR is relatively new and explanations aren't exactly concrete, a common belief is that discord between ocular input and vestibular stimulation is the cause — what your eyes see don't match up with what the balance-nerves in your ears are feeling. Your brain tries to figure out what's going on, and in the process you get sick. Nausea, headache, sweating, and dizziness are all common symptoms.
Full story from the WindowsCentral blog...