Dehydration

Dehydration occurs when your body doesn’t have the water it needs, having expelled more than you have taken in.

We lose water by sweating, breathing, burns, evaporation from mucous membranes, elimination (urinating, etc.) and by vomiting or diarrhea.

There are also bodily processes that tie up water and make it unuseful for general hydration. Digestion is a huge culprit here.

Thus dehydration isn’t always a heat injury. Even if you aren’t sweating a lot or doing anything else that seems like it should reduce your hydration, it can sneak up on you...

In dry heat, you sweat more than you realize; your sweat is doing what it’s supposed to do, which is to evaporate and thus help you keep cool. And you lose a lot by breathing dry air, as your mucous membranes need constant moisture.

But extremely cold air is also very dry. It’s freeze dried! So once again, your breathing is a major means of water loss.

There is a condition, hyponatremia (low sodium—loss of electrolytes), that sometimes is associated with dehydration. It is brought on by long, hard exertion with a lot of sweating or heavy exertion in great heat, or by vomiting or diarrhea.

Either condition (dehydration or hyponatremia) can kill you or leave you brain damaged, with possible failures in other organs, such as the kidneys. As with most conditions of outdoors and emergency activity, prevention is the best medicine.

Barring more-than-average losses of fluid, you can live roughly three days (not well) without water intake.

Prevention

• Drink lots of water. Drink before you’re thirsty. For some reason, our bodies don’t tell us that they need water until dehydration has started. That is, if you’re thirsty, you’re already somewhat dehydrated. Drink. Water. Four to eight glasses per day... with exertion, more
• Watch your urine. Urination every 3-5 hours and light-colored or clear urine are good signs
• With extreme circumstances (desert survival, diarrhea, etc.), use of hydration salts may be indicated to avoid hyponatremia. Be aware that if you are hyponatremic, water alone can make things worse. And don’t go overboard taking them; too much of a good thing is bad here
• If you are short on water, do not eat unless the food is very wet (soup, for instance). Digestion requires water, and you can find yourself dehydrated when you were ok before eating. I had this happen to me once before I knew better. Spooked me out and almost killed me!
• Particularly avoid exposure to causes for digestive illness. If it might make you sick, don’t eat or drink it; the sickness might not kill you, but it could cause dehydration/hyponatremia that could
• Avoid alcohol and caffeine. They dehydrate you
• Dress for the heat and reduce activity; reserve strenuous work for the cool parts of the day, and take advantage of shade, breezes, fans, air conditioners, etc.
• Give your body time to condition itself to the heat before big exertion. This may take a while (days and weeks), and will require that you push a little each day; just don’t get too far from relief and a “bottomless” water source
• Get enough sleep

Symptoms

• Mild to Moderate:
• Dry or “gooey” mouth
• Headache, red face, elevated body temperature
• Thirst, possible loss of appetite
• Decreased urine volume and/or dark urine, constipation
• Unexplained tiredness, loss of endurance, rapid fatigue
• Dizziness when standing
• Severe (the above possibilities, intensified, plus):
• Irritability, fussiness or confusion
• Dry skin and mucous membranes; may not sweat
• Little or no urination, or dark yellow or amber in color
• Sunken eyes
• Loss of skin elasticity; Doesn’t bounce back when compressed
• Low blood pressure
• Rapid heartbeat
• Fever
• Tingling in the limbs
• Delirium or unconsciousness

Treatment

• Avoid it in the first place!
• Drink water
• If you suspect the need for hydration salts (long, serious diarrhea or vomiting, or extreme heat/sweating) and don’t have a doctor handy for a medical evaluation, mix the below (a World Health Organization recipe conjured up during the 1960s):
• Table Salt - 3/4 teaspoon
• Baking Powder - 1 teaspoon
• Sugar -4 tablespoons
• Orange juice - 1 cup
• Water - 1 quart/liter
• Often tolerated in small, frequent sips, even in the face of nausea and vomiting, per MedicineNet.com
• Normally, water and maybe hydration salts (such as the solution above) should do it, but generally, for severe cases, if there is any way possible, get a medical opinion.

A word on treatment that seems especially important here: don’t do what you don’t have to do. If water does it, then leave it at water. There is a such thing as hypernatremia, which is overabundance of sodium. It too can be pretty ugly.

Electrolytes should be in the diet, and will be, unless there is malnutrition. But sometimes you come up short in desert summer heat. I do, anyway. And illness can do a number, too.

When I drink a lot of water and don’t feel relief, no matter how much I drink, that’s when I go for the salt. Plain ol’ table salt (not a lot; just a pinch!). Hyponatremia is lack of sodium, after all, but probably also indicates other electrolyte shortages. But for a quick fix when I’m close to home... then I make sure my diet has lots of fruits and vegetables—more than usual.

My favorite reference book for first aid matters is A Comprehensive Guide to Wilderness & Travel Medicine, by Eric A. Weiss. Handy, small, easy to pack around, but solid in its coverage.

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