Monday, December 10, 2012

Dehydration and Flying (It pays to be a plum than a prune)



This was strange. To a 26 year old, the vistas of the world are full of possibilities. Enchantment at every corner, love at every sight. But this one appeared agitated on a flight that he himself had requested. I attributed it to anxiety, which he promptly denied. He complained of a headache and muscle aches. This was a symptom complex with many probabilities.

Sherlock, I am not. So I landed the plane at a nearby airport down from sixteen thousand feet where we had been cruising for two hours. Remarkably after some Gatorade and a trip to the Restroom he was ready to go, all together in form and function. I was concerned but relented.


Slowly the bulb is lit and understanding burns brighter. In a word the answer was “dehydration.”
70% of the body weight is water based. 87% of that is inside the cell (intracellular). The “functional water” is required for oxygen enrichment and for maintaining the pH balance. Water is vital for blood, digestive juices, sweat and tears. Any discrepancy will lead to complications with delivery of these “humors,” including oxygen to the body cells creating a relative hypoxia. Thus balance leads to optimal health.

Not having which leads to the following complaints: Nausea, thirst, exhaustion, muscle and joint aches, anginal pain, migraine, restlessness and most importantly CNS symptoms like confusion, paranoia and anxiety.

Dehydration can occur as a result of high altitude, excessive exercise, sweating and deprivation.
The balance to maintain optimal body water level is coordinated by the kidneys mostly by concentrating urine. If the water is restricted or lost through vomiting, sweating or diarrhea, the osmotic pressure increases in the blood vessels that draws the water from the cells into the blood vessels. Similarly at altitude where the air pressure is low, the water vapor content is low and compensatory hyperventilation (increased rate of breathing) is a norm there is excess water loss through breathing - the exchange of dry air for moist breath. The shriveled cells slow down their function. The most damaging effect is in the brain. Alcohol at any quantity accentuates this effect, as does smoking. A pilot cannot afford that effect. Especially with the need for advanced decision making required in the cockpit.
Good hydration encourages the following: Increased energy, Reverse cellular damage, Normalization of the pH, Balance blood sugar, Fortify immune system, Better sleep, Clearer mind and Better memory.


Remember in commercial aircraft the pressure altitude at 35,000 feet is about 8,000 feet. This means that our bodies are at the 8,000 foot altitude. Hence the risk of dehydration even while you are sitting in a cramped economy or spread out in the first class, both classes are equally vulnerable to the effects of water loss. You breathe in drier air and breath out moisture laden one!

So what happens with continuous water loss, the blood becomes thicker and therein lies the other conundrum of blood clotting. That, I think we shall leave for another post in the near future.


So drink plenty of water before, during and after flight and at least five 8 oz glasses of water daily for optimal health. If you have to pee, so be it, that is why they have lavatories on commercial aircraft. For general aviation pilots, boys and girls you gotta land or use the indiscretion of the urinal.

Optimal performance is based on optimal health. If you are on your way to a meeting, interview or any business enterprise, it pays to be a plum rather than a prune.

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