Motion Sickness


  • Dehydration is the term given to a critical loss of water from the body

All aeromedical topics are GENERALIZED.
Always consult with a doctor or physician to understand your specific situation

Dehydration and Motion Sickness:

  • Dehydration is the term given to a critical loss of water from the body. Causes of dehydration are hot flight decks and flight lines, wind, humidity, and diuretic drinks—coffee, tea, alcohol, and caffeinated soft drinks. Some common signs of dehydration are headache, fatigue, cramps, sleepiness, and dizziness
  • The first noticeable effect of dehydration is fatigue, which in turn makes top physical and mental performance difficult, if not impossible. Flying for long periods in hot summer temperatures or at high altitudes increases the susceptibility to dehydration because these conditions tend to increase the rate of water loss from the body
  • To help prevent dehydration, drink two to four quarts of water every 24 hours. Since each person is physiologically different, this is only a guide. Most people are aware of the eight-glasses-a-day guide: If each glass of water is eight ounces, this equates to 64 ounces, which is two quarts. If this fluid is not replaced, fatigue progresses to dizziness, weakness, nausea, tingling of hands and feet, abdominal cramps, and extreme thirst
  • The key for pilots is to be continually aware of their condition. Most people become thirsty with a 1.5 quart deficit or a loss of 2 percent of total body weight. This level of dehydration triggers the "thirst mechanism." The problem is that the thirst mechanism arrives too late and is turned off too easily. A small amount of fluid in the mouth turns this mechanism off and the replacement of needed body fluid is delayed
  • Other steps to prevent dehydration include:
    • Carrying a container in order to measure daily water intake
    • Staying ahead—not relying on the thirst sensation as an alarm. If plain water is not preferred, add some sport drink flavoring to make it more acceptable
    • Limiting daily intake of caffeine and alcohol (both are diuretics and stimulate increased production of urine)
  • Heatstroke is a condition caused by any inability of the body to control its temperature. Onset of this condition may berecognized by the symptoms of dehydration, but also hasbeen known to be recognized only upon complete collapse
  • To prevent these symptoms, it is recommended that an ample supply of water be carried and used at frequent intervals on any long flight, whether thirsty or not. The body normally absorbs water at a rate of 1.2 to 1.5 quarts per hour. Individuals should drink one quart per hour for severe heat stress conditions or one pint per hour for moderate stress conditions. If the aircraft has a canopy or roof window, wearing light-colored, porous clothing and a hat will help provide protection from the sun. Keeping the flight deck well ventilated aids in dissipating excess heat

Private Pilot - Human Factors Airman Certification Standards:

  • Objective: To determine the applicant exhibits satisfactory knowledge, risk management, and skills associated with personal health, flight physiology, and aeromedical and human factors related to safety of flight
  • References: AIM; FAA-H-8083-2, FAA-H-8083-3, FAA-H-8083-25
  • Private Pilot - Human Factors Lesson Plan

Human Factors Knowledge:

The applicant demonstrates understanding of:

Human Factors Risk Management:

The applicant demonstrates the ability to identify, assess and mitigate risks encompassing:
  • PA.I.H.R1:

    Aeromedical and physiological issues
  • PA.I.H.R2:

    Hazardous attitudes
  • PA.I.H.R3:

    Distractions, task prioritization, loss of situational awareness, or disorientation
  • PA.I.H.R4:

    Confirmation and expectation bias

Human Factors Skills:

The applicant exhibits the skill to:


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