A new iPhone setting could help banish your motion sickness — if you turn it on. Roughly 50 per cent of adults suffer from nausea when travelling by plane , train or car. The problem is particularly acute for many when looking at a screen or book while on the move, making journeys extra tedious. Experts aren't entirely certain why some people suffer from motion sickness and others don't or why it happens at all. The broad theory is that the body is aware of its position in space thanks to