What should you know about space motion sickness?

Your eyes, inner ears and body send the brain information about movement and position. In space, weightlessness changes the usual inner-ear signals, so those messages may not match what the eyes see. The mismatch can lead to nausea, vomiting, dizziness, headache, sweating, tiredness and difficulty concentrating. Symptoms often improve as the nervous system adapts, but the timing and intensity vary between people.

Tell the flight medical team early, before nausea becomes severe. Keep head movements slow, use a stable visual reference when possible, and rest in a position that reduces spinning sensations. Follow the crew's instructions about prescribed preventive or symptom-relieving medicine. Small sips of fluid may be easier than a large drink after vomiting. Good hygiene helps protect others if vomiting occurs in a shared cabin.

Request urgent assessment for repeated vomiting, inability to keep fluids down, fainting, confusion, severe headache, new weakness, chest pain or breathing difficulty. Medical review is also needed when dizziness persists after motion exposure or symptoms are more severe than expected, because dehydration and other illnesses can resemble motion sickness.

Ask which medicines are suitable for your mission or journey, when they should be taken, and whether they can cause drowsiness. Discuss previous motion sickness, migraine, balance problems, pregnancy or medicines that could affect alertness.