People with pre-existing conditions could be at risk for injury caused by roller coaster rides. Those with underlying atherosclerosis of blood vessels might be prone to sheer stress and subsequent stroke. The excitement of the ride could release enough adrenalin to trigger both arrhythmia and infarction in susceptible individuals. Subdural hematomas and brain bleeding could happen even without direct trauma as violent movements of the head could tear cortical veins leading to the hematoma. This is rare and is more likely to happen to very young or old people, those taking blood thinners and long term alcoholics. Symptoms of subdural hematoma could be delayed by as much as 2 weeks and include fluctuating levels of consciosness, abnormal movement of the eyes, memory problems, nausea and headache. It can be diagnosed with CT or MRI. Roller coaster could also trigger headaches,vertigo, nausea, short-term memory loss and inflict ear injuries. Ear barotrauma occurs when there is a relatively quick change in pressure between the external environment, the ear drum and the pressure in the middle ear space. Otolaryngologists recommend that passengers remain facing forward for the duration of the ride to not let the full impact of acceleration hit the ear.
Hematomas and eye injuries have been documented after one roller coaster ride, yet there are healthy seniors able to tolerate dozens, almost a hundred rides per day. Young teenagers might be most susceptible to motion sickness symptoms, while toddlers are still calibrating their senses and enjoy the lack of predictability.