Dehydration and Nutrition

Dehydration impairs fatigue, cognition, and performance-especially in hot or high-altitude flights, requiring pilots to take care of themselves before conducting any flight operations.


Dehydration & Nutrition

Introduction to Dehydration & Nutrition

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

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

Dehydration & Nutrition

Dehydration and Motion Sickness

  • Dehydration is the term given to a critical loss of water from the body.
    • Causes of dehydration include hot flight decks and flight lines, wind, humidity, and diuretic drinks such as 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 it difficult, if not impossible, to achieve top physical and mental performance.
    • 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 you don't replace this fluid, fatigue will progress to dizziness, weakness, nausea, tingling in your hands and feet, abdominal cramps, and extreme thirst.
  • The key for pilots is to be continually aware of their condition.
    • Most people become thirsty when they have a 1.5-quart deficit or a loss of 2% of their total body weight.
    • This level of dehydration triggers the "thirst mechanism."
    • The problem is that the thirst mechanism activates too late and shuts off too easily.
    • A small amount of fluid in the mouth shuts off this mechanism, delaying the replacement of needed body fluid.
  • Other steps to prevent dehydration include:
    • Carrying a container to measure daily water intake.
    • Staying ahead-not relying on the thirst sensation as an alarm.
    • If plain water is not preferred, consider adding a sport drink flavoring to make it more palatable.
    • Limiting daily intake of caffeine and alcohol (both are diuretics and stimulate increased production of urine).
  • The body’s inability to control its temperature causes heatstroke.
    • You may recognize dehydration symptoms at the onset, or you may detect the condition only after it has progressed to a state of complete collapse.
  • To prevent these symptoms, carry plenty of water and drink it at frequent intervals on any long flight, whether you feel thirsty or not.
    • The body typically 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 protect from the sun.
    • Keeping the flight deck well-ventilated helps dissipate excess heat.

Dehydration & Nutrition

Private Pilot (Airplane) Human Factors Airman Certification Standards

Private Pilot (Airplane) Human Factors Knowledge:

The applicant demonstrates an understanding of:

Private Pilot (Airplane) Human Factors Risk Management:

The applicant demonstrates the ability to identify, assess, and mitigate risks encompassing:

Private Pilot (Airplane) Human Factors Skills:

The applicant exhibits the skills to:

Dehydration & Nutrition

Dehydration & Nutrition Conclusion

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Dehydration & Nutrition

Dehydration & Nutrition References