Motion sickness occurs due to a difference between actual and expected motion. Symptoms commonly include nausea, vomiting, cold sweat, headache, dizziness, tiredness, loss of appetite, and increased salivation. Complications may rarely include dehydration, electrolyte problems, or a lower esophageal tear.⁠ ⁠ The cause of motion sickness is either real or perceived motion. This may include car travel, air travel, sea travel, space travel, or reality simulation. Risk factors include pregnancy, migraines, and Meniere's disease. The diagnosis is based on symptoms.⁠ ⁠ Nearly everyone is affected by motion, and most will experience motion sickness at least once in their lifetime. Susceptibility, however, is variable: about one-third of the population is highly susceptible, while most others are affected only under extreme conditions.⁠ ⁠ ⁠ ⁠ ⁠ ⁠ ⁠ #motionsickness #sickness #inmotion #sick #menieredisease #biology #science