Keeping hydrated in the heat

Keeping hydrated in the heat
<http://www.drbriffa.com/2010/08/11/keeping-hydrated-in-the-heat/>

by Dr John Briffa
Posted on 11 August 2010

I'm a big believer in maintaining adequate hydration, and one reason for
this is that I and countless others have noticed just how this
relatively simple strategy can help enliven our physical and mental
energies. How much do we need to drink to maintain adequate levels of
hydration? Well, opinions are divided on this. Some say 8 glasses a day.
Some say that's rubbish. I say there is no hard and fast rule.

Why? Well, our need for water can be quite individual. Some people are
bigger than others. Some sweat more too. So, between individuals, there
can be considerable variation in what represents and optimal fluid intake.

But not only that, individual requirements can vary a lot within an
individual depending on a variety of factors including levels of
activity, humidity and, of course, temperature. A litre and a half of
water each day might be fine to maintain hydration levels if the
temperature is 15 centigrade (about 60 Fahrenheit). However, when the
ambient temperature is, say, 30 C (about 85 F), fluid requirements are
likely to be much higher.

I am currently in a part of southern Europe where the temperature during
the day is hovering around the mid-30s centigrade. Yesterday, I drank
what even by my own standards was a lot of water, but after my morning
wee, then next time I went to the toilet was about 1.30 pm. That itself
was not a good sign. And I also found that the urine I produced was
quite dark and, excuse me, pungent. Producing concentrated urine of this
nature is a pretty sure sign that the body is low on fluid.

Now, I reckon throughout the morning alone I downed about 2.0-2.5 litres
of water. However, it was clear from even a cursory glance at my urine
after lunch that the 2.0-2.5 litres had not been enough. And it reminded
me of just how important it is to gauge one's need for fluid not on some
generic recommendation based on volume, but on the basis of this an
individual indicator of hydration such as urine colour.

*My recommendation is to ensure that enough fluid is consumed to keep
the urine pale yellow throughout the day.* Be prepared on hot days for
this to be quite a lot more that you're perhaps used to drinking (as I
discovered yesterday).

As far as what to drink goes, my preference is to make the core fluid
water. Herb and fruit teas are good too, and perhaps even a bit of
regular tea and coffee if you like these (though the caffeine that these
may contain is a 'diuretic' and counter a bit the water you're drinking).

I'm not a fan at all of soft drinks. Some, however, find water a bit
dull. My suggestion is to put a little squeeze of lemon and/or lime in
some cold, sparkling water. A few crushed mint leaves are an idea too.

One other thing I've found in practice is that the more thirsty someone
gets, the less inclined they are to be satisfied by plain water. Once
someone has a thirst that really needs slating, soft drinks and beer
seem to become so much more appealing. Much more appealing than, for
instance, there is not particular thirst. So, the irony is, that many
find that drinking plenty of water makes it easier to be satisfied with
just plain water.