Pilots in training for situations where they will encounter G-forces go through a number of rigorous tests to make sure they can handle the high stress associated with things like stunt flying, piloting military aircraft, and riding in space ships and shuttles. This includes simulated conditions on the ground where pilots are put in an environment with very high acceleration stress to see how their bodies respond. Safety gear helps to prevent some injuries, and patients must regularly undergo health exams to make sure they are still fit for duty in environments where high G-forces will be present.