Varies: There is no specific dangerous heart rate during exercise. How fast your heart beats with exercise depends on a number of factors, especially your conditioning. If you are healthy, a heart reate in the 170's or even higher may be ok and tolerated.
Motion sickness caused by video games, sometimes called simulator sickness, is caused when there is a disconnect between what your eyes are seeing and what your body is feeling.
Motion sickness or sea sickness, car sickness, air or train sickness is a feeling of unwellness caused by movement and it's relationship to the inner ear and balance. Treatments include home remedies and OTC or prescription medications.