Thursday, July 5, 2012

Dehydration and Heatstroke


Dehydration

A critical loss of water from the body is dehydration. Causes of dehydration are hot flight decks, flight lines, wind, humidity, and diuretic drinks. Coffee, tea, alcohol, and caffeinated soft drinks fall into the category of diuretic drinks.. 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. The conditions above 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 the fluid the fatigue progresses to dizziness, weakness, nausea, tingling of hands and feet, abdominal cramps, and extreme thirst.

Hot weather, like this summer, requires vigilance for the symptoms ofdehydration . 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 will turn 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 offensive, 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

Your inability to control body temperature is heatstroke.   You can recognize the onset of heatstroke by the symptoms of dehydration. Complete collapse of your heat control efforts can occur without warning.

Carry an ample supply of water to prevent these symptoms. Use the water at frequent intervals on, long flight, whether thirsty or not. The body normally absorbs water at the 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 your aircraft has a canopy or roof window then 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. Phoenix, Arizona warns newcomers to stop frequently to drink water. Numerous drinking fountains are strategically placed to encourage you to drink. In very hot and arid conditions you lose water quickly and heatstroke is a constant danger. Same thing occurs in your plane.