Hydration/Dehydration/'Overhydration'.

Gentlefolk,

You need to be careful with rehydration - especially
in tropical climes.

Your body loses salt as well as water when you sweat
and if you replace only with pure water, eventually
you will develop 'water intoxication'.

This is, actually, not easy to achieve in a few hours
but can be done - typically in hospital, after surgery
- if only dextrose is given intravenously (because
the victim cannot take anything by mouth) rather than
dextrose/saline or just saline solution.

It is, however, quite possible in the flying context,
especially with prior sweating/pure water replacement
in a hot environment.

A reasonably early symptom is cramp (underground miners
used to get it by sweating a lot & replenishing only
with pure water - so-called 'miners' cramp').

Take to extremes, this syndrome can result in convulsions
& death - with mental impairment in between.

I suggest simple, diluted, fruit squashes.
These have ample salt - and occasional use will not
lead to galloping hypertension or any other, modern,
crime against humanity - unless, of course, you are
severely predisposed.

Opening pressurised bottles & cans at altitude is an
amusing hobby - if you like the contents splattered
all over yourself, your instruments and the canopy.
Coca Cola is particularly obnoxious !
Have been there, done it & wear the T-shirt !!

Cheers,

Stan.
UK.

Stan:

It's my understanding that the typical western diet includes such a
large overdose of salt (sodium chloride) that loss of salt through
sweating isn't usually enough to deplete the body's reserves, even in
hot climates. I believe that loss of potassium salts is usually the
problem.

I've lived in South Africa and now in Arizona and I drink nothing but
water when exercising or gliding. My only problem is that I have
suffered from mild leg cramps (usually at night), and most usually
after a long hike in hot, dry conditions.

I fixed this problem by upping my consumption of potassium-rich foods
(like dried apricots). I've never had to drink any of the sports
drinks, some of which look to me like anti-freeze. It probably doesn't
hurt that my favorite hiking snack is salted peanuts!

I wonder if some of the problems glider pilots experience result from a
combination of moderate dehydration together with mild hypoxia?

Mike

ASW 20 WA

Does beer have salt in it?