Warm water

[arthwollipot]

I've heard that you should always drink lukewarm water. If you drink cold water, the body has to expend energy to warm it up so that it can be properly absorbed. You urinate less often because the water is more efficiently absorbed by the cells when the water is warm.

This sounds like a load of rubbish to me, although I have heard a similar thing from a paediatrician. He said that it "lubricates the bowel" though, so the stories are not exactly the same.

Discuss.

[SomeGuy]

I've heard that you should always drink lukewarm water. If you drink cold water, the body has to expend energy to warm it up so that it can be properly absorbed. You urinate less often because the water is more efficiently absorbed by the cells when the water is warm.

This sounds like a load of rubbish to me, although I have heard a similar thing from a paediatrician. He said that it "lubricates the bowel" though, so the stories are not exactly the same.

Discuss.

I'm no physician but I think the first one makes some sense, heating stuff does require energy, but it doesn't need to be heated to be absorped it needs to be heated because your body likes being 37 degree celsius..

Being more efficiently absorbed, would require the water still being cold when it reaches your kidneys to make any difference that sounds like nonsense.

Lubricating the bowels, I have heard that one before sounds wooish put this way, but it does seem to work to take some warm water when obstipated, but that could very well be confirmation bias.

[Zep]

I suspect that the "lubricating the bowels" bit is an incorrect logical conclusion derived from the fact that lack of water in the body, say caused by sweating from severe overheating, can lead to constipation and slower peristalsis.

[Broes]

Lets assume:

The average body has a mass of 75 Kg
The content of a glass of water is about 0.3 Kg
The average body about 37 celsius
The average cold glass of water is about 15 celsius
The average warm water is about 25 celsius

This makes the ratio in mass 100 : 0.225 (or 1 : 0.00225)

Lets also assume that the heat exchange ratio between water and the human body is the same. By ingesting the glass of water, the water and the human body can quickly exchange heat given that the water is completely surrounded by the much large human body.

After drinking the cold glass of water, the body becomes 36.91 Celsius ((75x37)+(0.3x15))/75.3)
After drinking the warm glass of water, the body becomes 36.95 Celsius ((75x37)+(0.3x25))/75.3)

A whole whopping difference of 0.04 degrees Celsius...

[Professor Yaffle]

Well unless you are underweight to start with, why would you worry about drinking cold water causing you to expend a few calories?

[Southwind17]

Well unless you are underweight to start with, why would you worry about drinking cold water causing you to expend a few calories?

Good question. We don't worry too much about breathing in cool air, do we, which has the same effect.

[hipparchia]

Now, let me add another line of woo reasoning: food separation.

When you combine foods (e.g. meat and rice) your body will expend more energy to digest them. So, you will compensate by eating more and you will end up fatter, although you expend more calories.

If you drink more cold water, you will expend more calories, so you will eat more to compensate for this and end up fatter.

So, people who drink cold water with their steak and mashed potatoes will be fatter than people who drink a lukewarm glass of water, eat the steak first and and the potatoes an hour later.

Go figure...

[Southwind17]

I think this is, essentially, the basis of the Atkins Diet, but that, supposedly, has the opposite effect! I just loved eating the burgers and sausages out of curiosity. Oh well, in the gym again tonight!

[Zep]

Lets assume:

The average body has a mass of 75 Kg
The content of a glass of water is about 0.3 Kg
The average body about 37 celsius
The average cold glass of water is about 15 celsius
The average warm water is about 25 celsius

This makes the ratio in mass 100 : 0.225 (or 1 : 0.00225)

Lets also assume that the heat exchange ratio between water and the human body is the same. By ingesting the glass of water, the water and the human body can quickly exchange heat given that the water is completely surrounded by the much large human body.

After drinking the cold glass of water, the body becomes 36.91 Celsius ((75x37)+(0.3x15))/75.3)
After drinking the warm glass of water, the body becomes 36.95 Celsius ((75x37)+(0.3x25))/75.3)

A whole whopping difference of 0.04 degrees Celsius...This all assumes you do not generate any more heat whatsoever during the drinking phase of the experiment!

[Cuddles]

Water has a heat capacity of about 4 Jg-1K-1. Using Broes' assumption of 0.3kg for a glass of water, that means the energy needed to heat up a glass of water from 15oC to 37oC is 300*4*17 = 20,400J = 5,100 Calories. The labels on food are actually in kJ and kCal. According to the bag of crisps (possibly chips if you're American) next to me, one 35g bag contains 752kJ. That means that to replace the energy used in heating a glass of water you would need to eat approximately one crisp, possibly less. Don't plan on losing weight by drinking cold water any time soon.

[Blue Bubble]

Oh my, it's only a matter of time before the homeopaths get wind of this, and start selling their stuff to be taken extra-cold to counteract obesity.

[Rasmus]

I'm gonna have me some ice cream.

[Southwind17]

Water has a heat capacity of about 4 Jg-1K-1. Using Broes' assumption of 0.3kg for a glass of water, that means the energy needed to heat up a glass of water from 15oC to 37oC is 300*4*17 = 20,400J = 5,100 Calories. The labels on food are actually in kJ and kCal. According to the bag of crisps (possibly chips if you're American) next to me, one 35g bag contains 752kJ. That means that to replace the energy used in heating a glass of water you would need to eat approximately one crisp, possibly less. Don't plan on losing weight by drinking cold water any time soon.

This doesn't seem right to me. If I heated the glass of water by lighting and burning said crisp beneath it (assuming no heat is wasted) I'm struggling to see how it could raise the temperature by so much. The burning process would probably, I guess, last a matter of seconds only.

I'm probably missing some important aspect of physics, but intuitively, something seems awry. Could it be the Cal to kCal conversion?

[Cuddles]

This doesn't seem right to me. If I heated the glass of water by lighting and burning said crisp beneath it (assuming no heat is wasted) I'm struggling to see how it could raise the temperature by so much. The burning process would probably, I guess, last a matter of seconds only.

I'm probably missing some important aspect of physics, but intuitively, something seems awry. Could it be the Cal to kCal conversion?

I've bolded the important part.

[SomeGuy]

This doesn't seem right to me. If I heated the glass of water by lighting and burning said crisp beneath it (assuming no heat is wasted) I'm struggling to see how it could raise the temperature by so much. The burning process would probably, I guess, last a matter of seconds only.

I'm probably missing some important aspect of physics, but intuitively, something seems awry. Could it be the Cal to kCal conversion?

You are underestimating how much heat is lost when you burn something underneath a glass or pan etc...

Try to pretend it completely burns inside the water... there are still significant losses, but I think even intuitively you can see this would yield a larger heat gain...

[Southwind17]

OK - I thought it would be something like that. Just shows you eh how much energy we must waste!

[Professor Yaffle]

On a quick google, I found the following doozy:


Drinking hot water after meals reduces cancer risk. Let me explain how. Drinking cold water will solidify the oil part of the food we have eaten. This will slow down the digestion process. And when this sludge reacts with the digestive enzymes and acids, it will break down and will start getting absorbed by the intestine faster than the solid food. This lines the intestine. The consequence is that this will turn into fats and lead to cancer. Therefore it is best to drink hot soup or warm water after a meal.

Cold water can also in extreme circumstances lead to heart attacks. As we have our meals enzymes and acid secretions start and this process sort of warms up the body. Drinking cold water is like attacking the body with an exactly opposite temperature. Not only does the whole procedure of digestion gets interrupted or slows down, the body can also react in the form of a heart attack. It does not always come after a pain in the right arm or pain in the chest.


http://www.healthoma.com/a-glass-of-hot-water-after-meals-reduces-cancer-risk/

[Southwind17]

Food for thought!

[Professor Yaffle]

Apparently the question of warm or cold water is significant for the milk yield in dairy animals! You learn something new every day (and most of it will be of no use to you at all).

http://jds.fass.org/cgi/content/abstract/73/4/1091

http://www.blackwell-synergy.com/doi/abs/10.1046/j.1365-201X.1996.d01-727.x

http://ltnet.lv-h.de/en/volltext/Lt20004/LT20004E_ATF_097_101.pdf

http://ltnet.lv-h.de/en/volltext/Lt20004/LT20004E_304_305.pdf

[Broes]

question of warm or cold water is significant for the milk yield in dairy animals!

I also bet they drink a bit more then 0.3 liters :)

[Wheezebucket]

I heard this from people all the time when I lived in China. I told em to shove off, because warm water is gross, and Zeus made ice for a reason - to keep our drinks cold. My logic won over a lot of hearts and minds.

[Gord_in_Toronto]

Since the body produces excess heat at pretty much all times (excluding Winters in Winnipeg), surely the energy required to heat the water would have to be disposed of anyway (by perspiration, for example).

[Cainkane1]

Yeah but cold drinks on a hot day are so pleasant to drink. May not be a good idea but it sure is pleasant.

[Professor Yaffle]

If cold water is bad for you, will my ice cube crunching addiction kill me?

[Lisa Simpson]

My sis-in-law's pediatrician told her not to bother heating up her baby's bottle because as soon as it got inside it would be heated up to body temperature. I'm happy to report my niece is alive and well and going to the Homecoming Dance this Saturday night.

By the logic used in the OP, one should eat all of one's food and drink at body temperature (which would be dangerous, BTW). Hot food has to be cooled down to body temp and cold food has to be warmed up. Warm beverages can have a laxative effect, which could be the lubricating the bowels silliness.

[JoeEllison]

The way I understood it, the claim is that colder water just doesn't absorb as quickly, that it sits in the stomach until it warms a bit before moving to the rest of the body. Could that part be true?

[Lisa Simpson]

Not according to any of my nutrition textbooks. And like I said, my niece's doctor said as soon as it hit the body, it warms up.

[Jimbo07]

Not according to any of my nutrition textbooks. And like I said, my niece's doctor said as soon as it hit the body, it warms up.

Which of course isn't technically possible because heating takes some some finite amount of time (even near catastrophically exothermic processes :boxedin:).

[Professor Yaffle]

A couple of places I found he opposit assertion - that cold water is absorbed more quickly than warm. Not sure how reliable their info is either. This quote is from the Urban Legends site.

http://urbanlegends.about.com/library/bl_drinking_cold_water.htm


What studies do exist mainly extoll the benefits of drinking cold water, especially during and after vigorous exercise. Cold water is absorbed by the body more quickly than warm water and can help lower one's body temperature, preventing dehydration.


And this from a dietician's website:

http://www.dietitian.com/fluids.html



Q. I've noticed recommendations for cold water a couple of times recently. Is there a difference between room temperature and cold water as far as how the body uses it?


A. Cold (40 - 50 degrees F) water is absorbed more quickly from the stomach. Also, if cold water is drank during physical exercise has the dual effect of also cooling the internal body temperature along with sweat produced by exercise. Since sweat is your body’s way of cooling itself, leave sweat on your skin and you should feel cooler.

[rudar]

I doubt it makes much difference under normal conditions. One morning while winter camping in a snow cave at about 15-20 C below, I determined that I was a bit dehydrated, and slammed back a full liter of water before noticing that it *wasn't* the bottle I had had in my sleeping bag overnight, and was in fact starting to freeze over. That definitely chilled me to the core, and it was a good half-hour of focussing on getting warm again before I could continue with the breaking-camp routine. But I don't think that qualifies as normal conditions.

[fishbob]

Lets assume:

The average body has a mass of 75 Kg
The content of a glass of water is about 0.3 Kg
The average body about 37 celsius
The average cold glass of water is about 15 celsius
The average warm water is about 25 celsius

This makes the ratio in mass 100 : 0.225 (or 1 : 0.00225)

Lets also assume that the heat exchange ratio between water and the human body is the same. By ingesting the glass of water, the water and the human body can quickly exchange heat given that the water is completely surrounded by the much large human body.

After drinking the cold glass of water, the body becomes 36.91 Celsius ((75x37)+(0.3x15))/75.3)
After drinking the warm glass of water, the body becomes 36.95 Celsius ((75x37)+(0.3x25))/75.3)

A whole whopping difference of 0.04 degrees Celsius...

The ice-water weight loss program:

Average cold water with ice cubes floating in it - about 1 degree Celsius -
per liter, warmed to body temp is 36 Kcal. Plus all that running to the bathroom burns off even more of those unwanted calories.

[Kilgore Trout]

Along with the idea of drinking cold water during exercise, perhaps the idea might be that it cools the stomach (and the esophagus, etc) causing the body to (over?) react and try to raise the body's temperature, thus expending energy. Very cold water may shock the system into thinking there is something very wrong, too. The end result may be (based on pure speculation on my part) a body temperature higher than normal, and then even a bit more energy expended to reach equilibrium.

[plumjam]

lol
come on guys, life's too short

[arthwollipot]

I've unleashed a monster!

Thanks everyone for enlightening me on this subject.

[Foster Zygote]

Well unless you are underweight to start with, why would you worry about drinking cold water causing you to expend a few calories?

Living in a part of the world where it's close to 100F and very humid in the summer I need the extra cooling I get from a big, cold glass of water.

[Soapy Sam]

I'm mildly amazed nobody has mentioned British "warm" beer.

[Miss Anthrope]

Oh my, it's only a matter of time before the homeopaths get wind of this, and start selling their stuff to be taken extra-cold to counteract obesity.

It's already happened, trust me, I have a first hand anecdote.

Also, it's all over places like weight watchers and such as gospel.

[bruto]

Oh my, it's only a matter of time before the homeopaths get wind of this, and start selling their stuff to be taken extra-cold to counteract obesity.
But wouldn't they then have to diminish the coldness past the vanishing point by serving their cold water hot?

[DevilsAdvocate]

I've heard that you should always drink lukewarm water. If you drink cold water, the body has to expend energy to warm it up so that it can be properly absorbed.Isn't this fundamentally ridiculous? The expended energy from drinking a cold glass of water is so minute it is irrelevant. Instead of drinking warm water, you could put on a hat for ten minutes, or a jacket, or a heavier shirt; or move closer to the radiator for a few seconds; or eat something slightly warm; or walk around for a few seconds. It won’t matter. There are many, many more things that affect your body that make the temperature of a glass of water insignificant.

[blutoski]

Isn't this fundamentally ridiculous? The expended energy from drinking a cold glass of water is so minute it is irrelevant. Instead of drinking warm water, you could put on a hat for ten minutes, or a jacket, or a heavier shirt; or move closer to the radiator for a few seconds; or eat something slightly warm; or walk around for a few seconds. It won’t matter. There are many, many more things that affect your body that make the temperature of a glass of water insignificant.

Basically. The fact of the matter is that the body is constantly producing more heat than it needs, and is expelling it. Mostly, to heat up the immediate environment (air, seat cushion, &c). Room temp is between 20-25C. Body temp is 37C.

When you drink cold water, some of the energy that was being wasted in one way will be temporarily diverted to heating the water to body temp. Your body doesn't have to burn 'extra' calories to do this.

Having said that: there are extreme situations where your body is in an environment that is either too hot or too cold for normal operations to mitigate. We can die of heat exhaustion/stroke or hypothermia. The case of the camper drinking icewater is an example of the latter: the body needs to go to extreme measures to adapt, and may fail. In which case, drinking hot or cold water can be critical.

But under normal circumstances, there is no 'energy' benefit to drinking warm water. Warm water is probably also at room temperature, say, 20C, which means the body is *still* warming it up to 37C. Water at body temperature would probably feel 'hot'.


Having said that, there is a noticeable effect from drinking hot/cold liquids when within the normal body temperature range. The reason is that the esophagus is close to the pulmonary vascular system, as well as the cardovascular system. Cold drinks can cool down blood passing nearby, and perhaps even pass to the brain through the carotids. This effect will 'trick' the body into thinking it is a different temperature, and provide some brief relief, while the body takes a moment to regulate temp according to surroundings.




The second discussion about digestion is also unrelistic, and much goofier. The body doesn't absorb water until it passes throuh the large intestine, which is to say: water absorption is the last thing the body does to a bolus before excretion. There is no delay in the stomach. Even if that was true, hesitation for thirty seconds can't have a noticeable effect on overall digestion.

[LostAngeles]

My sis-in-law's pediatrician told her not to bother heating up her baby's bottle because as soon as it got inside it would be heated up to body temperature. I'm happy to report my niece is alive and well and going to the Homecoming Dance this Saturday night.

By the logic used in the OP, one should eat all of one's food and drink at body temperature (which would be dangerous, BTW). Hot food has to be cooled down to body temp and cold food has to be warmed up. Warm beverages can have a laxative effect, which could be the lubricating the bowels silliness.

Off-topic: Just so I'm clear, you heat the bottle to sterilize it, don't you?

[Broes]

I did once eat 20+ ice popsicles in about 1.5 hours when it was scorching hot outside...
Yes my tummy didn't like that...
Started complaining alot, my tummy did...
Then I thought to make it feel a bit better by drinking some warm water...
Then I almost passed out...

So don't eat 20+ ice popsicles!

[fuelair]

I am told , some reliably, that if you put a sleeping person's hand in lukewarm/warm water they will lose a few ounces.

[arthwollipot]

Isn't this fundamentally ridiculous? The expended energy from drinking a cold glass of water is so minute it is irrelevant. Instead of drinking warm water, you could put on a hat for ten minutes, or a jacket, or a heavier shirt; or move closer to the radiator for a few seconds; or eat something slightly warm; or walk around for a few seconds. It won’t matter. There are many, many more things that affect your body that make the temperature of a glass of water insignificant.

I thought it was ridiculous myself, which is why I checked with the most experienced skeptics I know before getting to the debunking.