Comments on: Water temp to maximize hydration speed?

Question: Water temp to maximize hydration speed?

Humpable Prose — Tue, 26 Dec 2006 20:02:53 -0800

What temperature water will hydrate one fastest?

Is it hot, cold, or somewhere in between? (And why?)

My friend says hot water is best. In which case, is cold water "refreshing" only because of its thermoregulatory properties, not because of how fast it quenches one's thirst?

By: quin

quin — Tue, 26 Dec 2006 20:17:13 -0800

I have no science to back this up, but I always drink my water at room temperature because too hot or too cold prevents me from using my preferred method which is drink half the bottle in a single pull.

So as a sample size of one, I personally get hydrated most quickly by having the water neither too hot or too cold, but just right.

By: stavrogin

stavrogin — Tue, 26 Dec 2006 20:32:30 -0800

Comparison of Efficacy of Oral Rehydration Fluids Administered at 37°C or 23°C

"There were no differences between the groups with respect to weight gain, rapidity of rehydration, frequency of vomiting, or overall efficacy. Nor were there differences between infants rehydrated using the rotating 2:1 (GES:water) or bolus 2:1 oral rehydration methods. Oral rehydration fluids can be administered at ambient temperatures and need not be warmed to 37°C."

By: jamjam

jamjam — Tue, 26 Dec 2006 21:13:35 -0800

In the most common conditions where a healthy person might seek rehydration-- you are hot and sweaty from exercise, or it's a really hot day and you're thirsty-- I think cold water will rehydrate fastest, because the cold water will quickly lower body temperature, which will reduce sweating, evaporation from sweating, and evaporation from your lungs and the mucus membranes of your breathing passages, all of which are sources of water loss which would continue at higher rates if you drank hot water instead.

By: Steven C. Den Beste

Steven C. Den Beste — Tue, 26 Dec 2006 21:21:17 -0800

Water in your stomach will rapidly come to ambient temperature -- i.e. ambient inside your body. The temperature it was when you drank it will only matter for a minute or two. After that, it's all the same temperature.

By: Camel of Space

Camel of Space — Tue, 26 Dec 2006 21:31:20 -0800

Room temperature is best. Too cold and your body does too much work to warm it up, and so it goes through you. Too warm, and it has to cool down inside of you.

You shouldn't drink a lot of water all at once, as it doesn't hydrate you as well. Instead, you should take it in all day.

By: TrashyRambo

TrashyRambo — Tue, 26 Dec 2006 21:44:25 -0800

My biology teacher once told me iced water can lower core temperature and so convince your body it's cold (despite you being hot peripherally due to muscle activity). It'll then step up sweating, etc.

But I can't find a ref on a (rather cursory) Google search, so maybe not true.

By: quin

quin — Tue, 26 Dec 2006 22:04:01 -0800

Camel of Space : You shouldn't drink a lot of water all at once, as it doesn't hydrate you as well. Instead, you should take it in all day.

Bah, despite the eponysterical-ness of your comment, you clearly have never suffered the harsh recriminations of a badly spent night-out-on-the-town. Sure it might be "better for you" to slowly take in water, but when you are desperately hung over with no hope for parole, chugging water is the fast track to less pain.

Just sayin'

By: MonkeySaltedNuts

MonkeySaltedNuts — Tue, 26 Dec 2006 22:05:48 -0800

Actually you should not be concerned with the temperature but with the frequency of re-hydration.

As a young adult I worked several jobs where I was kept out in the heat too long. Some times it almost seemed that I had gotten so dehydrated that I was no longer able to sweat. Afterwards when I could guzzle water I shortly broke out in a freaky body covering layer of sweat.

The temperature of water has nothing to do with "rehydtation". However if somebody is so dehydrated that their core body temperature has risen then they would appreciate some cold water to lower this temperature.

I wish you luck with applying these lessons from people who have really sweated to your (maybe personal trainer) lifestyle.

By: rhizome

rhizome — Wed, 27 Dec 2006 00:00:50 -0800

Monkey is closest to what I've come across in writings about hydration and cycling. The study that I came across said that (for some reason), people drank cold water less frequently, but not because it was a shock to the system. It wasn't the temperature per se that affected hydration rates or anything, it was just that the lower the temperature the less frequently people felt like drinking.

By: vacapinta

vacapinta — Wed, 27 Dec 2006 11:09:50 -0800

Room temperature is best. Too cold and your body does too much work to warm it up, and so it goes through you. Too warm, and it has to cool down inside of you.

I've always had a question about this. Wont your body warm it to body temperature anyways? So by that argument shouldnt you be drinking 98 degree water?

By: mr_silver

mr_silver — Wed, 27 Dec 2006 13:09:56 -0800

On a completely non-scientific basis, I'd argue that cold water rehydrates people better simply because warm water tastes horrible.

As such, they drink more of it.

By: bad grammar

bad grammar — Wed, 27 Dec 2006 18:59:36 -0800

On a completely non-scientific basis, I'd argue that cold water rehydrates people better simply because warm water tastes horrible.

I second this: I cannot get over the impression that plain hot water (not a vehicle for coffee, tea, lemon juice and sugar, etc.) tastes like bath water. Exercising in very hot weather, you take your water bottle along, and the water heats up to ambient temperature. Disgusting.