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 from car travel, air travel, sea travel, space travel, or reality simulation. Risk factors include pregnancy, migraines, and Ménières disease. The diagnosis is based on symptoms.Treatment may include behavioral measures or medications. Behavioral measures include keeping the head still and focusing on the horizon. Three types of medications are useful: antimuscarinics such as scopolamine, H1 antihistamines such as dimenhydrinate, and amphetamines such as dexamphetamine. Side effects, however, may limit the use of medications. A number of medications used for nausea such as ondansetron are not effective for motion sickness.Nearly all people are affected with sufficient motion and most people will experience motion sickness at least once in their lifetime. Susceptibility, however, is variable, with about one-third of the population being highly susceptible while most other people are affected under extreme conditions. Women are more easily affected than men. Motion sickness has been described since at least the time of Homer (c. eighth century BC). Signs and symptoms
Symptoms commonly include nausea, vomiting, cold sweat, headache, dizziness, tiredness, loss of appetite, and increased salivation. Occasionally, tiredness can last for hours to days after an episode of motion sickness, known as "sopite syndrome".
As evidenced by the following:

Compulsive behavior and/or mental preoccupation regarding affirmative and restrictive dietary practices believed by the individual to promote optimum health. (Footnotes to this criteria add: Dietary practices may include use of concentrated "food supplements." Exercise performance and/or fit body image may be regarded as an aspect or indicator of health.) Violation of self-imposed dietary rules causes exaggerated fear of disease, sense of personal impurity and/or negative physical sensations, accompanied by anxiety and shame. Dietary restrictions escalate over time, and may come to include elimination of entire food groups and involve progressively more frequent and/or severe "cleanses" (partial fasts) regarded as purifying or detoxifying. This escalation commonly leads to weight loss, but the desire to lose weight is absent, hidden or subordinated to ideation about healthy food.Criterion B. The compulsive behavior and mental preoccupation becomes clinically impairing by any of the following:

Malnutrition, severe weight loss or other medical complications from restricted diet
Intrapersonal distress or impairment of social, academic or vocational functioning secondary to beliefs or behaviors about healthy diet
Positive body image, self-worth, identity and/or satisfaction excessively dependent on compliance with self-defined "healthy" eating behavior.A diagnostic questionnaire has been developed for orthorexia sufferers, similar to questionnaires for other eating disorders, named the ORTO-15. However, Dunn and Bratman critique this survey tool as lacking appropriate internal and external validation. Epidemiology
Results across scientific findings have yet to find a definitive conclusion to support whether nutrition students and professionals are at higher risk than other population subgroups, due to differing results in the research literature.