If life were a Mad Maxx movie, death by dehydration would involve deserts and grimy men with lots of beard stubble. Since most of life is not Hollywood, death by dehydration mostly looks like a baby with diarrhea. Or a toddler who’s had a bad fever for several days. Maybe it looks like an adult prostrated with heat who can no longer sweat. Whatever its face, dehydration is a lot more dangerous than mutant biker gangs in the real world.
How can we recognize this problem when its developing, and what should we do about it if there’s no medical professionals around to help? I’m not a physician (and this is not me giving you medical advice), but here’s some of the ideas the medical people have to offer.
Why is dehydration such a problem?
We’re seventy percent water. Losing ten percent of that should be no big deal, right? Not at all.
The biggest problem is blood volume. Our blood is roughly half water. Dehydration lowers blood volume. Having too little fluid (blood) in the pipes (blood vessels) naturally reduces the pressure in those pipes (blood pressure). Blood pressure is critical for moving blood around and making it do its job of exchanging materials from distant parts of the body.
Worse, the kidneys use blood pressure to do their job of removing wastes from the blood for disposal. Low blood pressure causes kidney failure, and that’s fatal in less than a week without serious medical intervention.
A second problem is blood viscosity. Normal blood is pretty watery in consistency, as we’ve all seen. Lose much water, and the other half of the blood (the red blood cells) make the blood thicker, so it flows more like maple syrup than water. It gets hard to push through the little blood vessels.
There’s also overheating. When our bodies go into water conservation mode to keep the blood pressure up, they won’t let us sweat. Since sweating is our main cooling mechanism, that is a potentially fatal problem.
Sources of dehydration
Dehydration from diarrhea is the single biggest killer of people under five years of age in the world. Not only is diarrhea very common in the young, especially hygiene is sketchy, but the dehydration that comes with hits harder and kills sooner in the very young. (The very old are also at increased risk.)
Other kinds of illness will help dehydration sneak up on you, too. Vomiting loses fluid and discourages replacing it. Fever is especially sneaky, because you don’t see the water being blown away on the breath, but it’s leaving you all the same. High elevations and otherwise dry air make this respiratory dehydration even worse.
Low intake and high sweating are also causes of dehydration, but that’s no surprise.
Signs that dehydration’s becoming a problem
Symptoms of dehydration the victim can notice: Thirst of course, but they might not notice that if very ill. Dry mouth, often noticed when trying to chew dry foods.
Signs of dehydration anyone can see: The eyes become sunken. In infants, the soft spot at the back of the skull (the fontanel) sinks in. When the skin is pinched a bit, it ‘tents’, meaning that the pinched bit holds its peak for a bit before springing back into place. The urine is scanty and dark yellow. (If there is no urine, it’s an emergency!) There’s little sweating even when the skin is red and hot.
This is what skin tenting from dehydration looks like.
Signs you can notice if you’re on the lookout: If you are worried about dehydration, you can take the person’s weight and/or blood pressure early on, then again periodically. Both drop as dehydration progresses. The pulse speeds up to try to compensate, too.
What can be done about dehydration?
Well of course feed them fluids. Less obviously, feed them fluids even if they’re vomiting a lot. Some still gets absorbed. What fluids? First, what they’ll drink. A large person will need 3 or more liters of water a day. For a child, a glass of fluid for each watery stool is the goal.
If it’s a baby, breastmilk is best. For anyone else, rehydration drink is a good choice to combat dehydration. Half a level teaspoon of salt and 8 level teaspoons of sugar, with half a cup of fruit juice or half a mashed banana for potassium if possible, is used per liter of water. (A 16 oz drink bottle is almost half a liter (473 ml), for you English units folks.)
Directions on making rehydration drink from Where There Is No Doctor
My friend Doc (who is an actual physician) likes Nuun electrolyte tablets for rehydration after a hard desert hike. They also taste nice enough she’ll drink the stuff, which is important. (We have zero financial relationship with any seller.)
These pack easily and are pretty shelf-stable. I got fewer cramps when taking them after hard hikes, for whatever a sample size of one is worth.
Besides giving fluids…
Food has water in it too, so don’t be shy about offering what they’ll take.
In the short term, raising the feet above the head gives a temporary rise of blood pressure in their core. Quick-dry cloth can be wetted and laid over a dehydrated person who’s not sweating well to aid cooling.
Dehydration is not something to be messed around with. It’s best to avoid it, second best to treat it promptly. The worst idea is to try to ‘tough it out’ or ignore it.
Of course, IV fluids are a quick, effective solution; but if you’re capable of that you probably don’t need any advice from this direction.
Note: Many of the suggestions here come from a great prepper resource, the book Where There Is No Doctor by David Werner (we review it here). (1) This is the same basic advice as many other sources provide, but it’s particularly well and succinctly put by Werner.
1) Werner, D. (2011) Where There Is No Doctor: A Village Health Care Handbook (rev). Hesperian Health Guides, Berkeley, CA.