Zeraph

So I was camping and it was cold. My friend goes "pee if you get cold, since your body will expend less energy keeping the extra liquid body temp."

That got me thinking. It's kind of moot since when you have to pee, you have to pee. But it applies to other stuff too. Like is an empty house more easily kept warmer because it has less stuff in it to warm?

It seems that starting from neutral and increasing temp would make a difference if you had extra matter in the equation, because it will absorb some of that energy, but if you've already drunk the water, and your body has already heated it, then I'm not sure it follows if it would require more energy to continue keeping your pee warm.

Any math/physics gurus that can confirm?

Hektore

If the cold is a problem at night, and if peeing at night means crawling out of your sleeping bag and exposing yourself to even colder air outside the tent to get it done, then it totally wouldn't be worth it to me. Especially when you consider that you're going to have to 'reheat' your bag by the time you return.

Wear and extra shirt/sweats.

My inclination is no, it doesn't make any difference for the reason you stated. The liquid has already been heated, and if anything holding it will work better to keep you warm because the added heat reservoir in your bladder will be more total volume to cool, before you die of hypothermia.

What may help, if you're not already dehydrated is abstaining from water/cold foods which would cool your core when you eat/drink them.

As for the house, in a house you heat the air, which is also what your thermostat measures. So, in theory a fuller house has less air to heat, as for heating the stuff in the house, the more stuff the more it takes to heat it. I don't know that this is answerable for certain without considering what the house is filled with.

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Xerxys

^^ I'm not too sure. When it's cold, you pee. It keeps you warm. Yes the body has already heated the fluid but maintaining the heat is the biggie. When you expend the fluid the better the body circulates the heat instead of collecting it in your abdomen.

Daniel_

If you fill the house with things that have a higher heat capacity than air (as most things do) it will take longer to warm up - this leads some people to conclude that it must take more energy to keep your house to temperature.

The problem is that the other side of the equation is that when your heating shuts off, those items release their heat more slowly than air would have, and therefore delay the heating system from re-starting (thus saving you energy).

On balance, what this does is slow down the cycles of your heating system.

Seeing as each time your heating system cycles (from fully cold to fully hot to fully cold again) there are fixed losses, regardless of how long it's on for, anything that reduces the number of cycles it goes through saves you energy.

Therefore in the long run, thermodynamics demonstrates that a filled house takes less energy to heat than an empty one.

Status: BUSTED

As for the urine argument, it is true that your body uses less energy to keep X kg warm than it does to keep X + Y kg warm.

The problem is, that if you pee out Y kg of urine that is warmer than its surroundings, you loose all of the heat you invested in warming up that pee to start with.

Even if you pee into a bottle and keep that inside your clothes to retain the heat it won't help, as you are moving a warm mass of pee from your core (where it is well insulated) to your outer layers (where it will bleed heat).

All in all, whatever you do it's about the same, but as with the heating system argument, the fewer times you cycle hot-cold-hot (i.e. open your clothes and loose heat while you wee) the less you suffer, so the best option is to allow your bladder to fill as full as you can manage, and then pee as rarely as you can.

Status: BUSTED

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Gebbinn

The third and fourth paragraph of the article found at this Link answer this question. The first paragraph applies to winter months, and the second to summer months.

As for the pee, I would have to say that it doesnt really matter, if I have to pee, I cant sleep, so I end up getting out of the sleeping bag to pee anyway. As for staying warm in a sleeping bag, contrary to popular opinion, you actually stay a great deal warmer in a sleeping bag if you have fewer clothes on. (assuming the bag is actually rated for the ambient temperature.. a 20degree bag is going to be useless at -20 degrees.) Sleeping bags are designed to trap your bodies heat inside the bag, and thus insulate you from outside temperatures. If you wear clothes, your clothes trap that heat and the bag takes a great deal longer to provide the insulation. In the long run, the sleeping bag will work about the same with or without clothing being worn, the speed at which it warms the user is greatly dependent on that same matter. Now I could be wrong, and if I am someone will correct me, but that is what they taught us in the army.

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ratbastid

How about this: when you pee you lose the heat that's already in the urine. The net effect is to cool you down. So don't pee when you're cold--pee when you're hot!!

yournamehere

One thing I know for sure - don't pee your pants. Evaporation is a cooling process.

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ratbastid

When I was a wee teenager, a minor civil infraction involving beer and bottle rockets netted me some public service hours (for littering--they waved away the underage drinking charges!) which I spent under a bridge feeding the homeless EARLY EARLY several Sunday mornings.

One morning it was 10 below zero under that bridge. Cold as a mother fucker. At some point, I realized, here I am carrying bowls of warm soup. And my toes feel like they're going to freeze right the fuck off. And I have warm soup in my hands, sloshing in this styrofoam bowl. And my toes are cold as ice.

That day I learned two things: Soup freezes solid in about three minutes, and it's hard to get the smell of minestrone out of a pair of Chuck Taylors.

jewels

Jeesh. Learn sumpin' new every day. And I thought it was as simple as knowing that you expend calories trying to hold it in thus keeping your body temperature higher ... ?

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achillesheel

I dunno about peeing/holding it but, next time you go camping take a rated sleeping bag (-15 degrees or so usually works fine) and strip down to your boxers/underwear. You might think wearing more clothing would keep you warmer but the bags are designed to work WITH your skin/body heat.

yournamehere

Alcohol and gun powder. Lovely combination.

Well, at least you grew out of it. Our State Legislature, in its reactionary glory at having a Republican Governor again, just passed a couple of bills for her signature. One includes allowing the sale of fireworks on "drinking holidays" in a state that is basically a 114,000 sq. mile tinderbox; the other bill now allows people to carry guns in bars.

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If you want to avoid 95% of internet spelling errors:
"If your ridiculous pants are too loose, you're definitely going to lose them. Tell your two loser friends over there that they're going to lose theirs, too."
It won't hurt your fashion sense, either.

Hektore

You know, this has been said twice now, and It's not quite true. Yes, if you wear clothing inside a sleeping bag, then you lower the efficacy of the bag. BUT (big but) you've increased the usefulness of the clothing, because the air around it is warmer. so while the temperature just inside the bag is cooler, the temperature inside your clothing (and right next to your body) is warmer.

By the logic in the quote putting my 50 degree sleeping bag (which is nothing more than a fleece blanket with a zipper) inside my 20 degree bag actually would make me colder. I can assure you this is not the case.

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Zeraph

Yeah, I can testify to this. I've camped in some really, really cold places. It's much more effective to leave all my clothes on. It takes an hour or two for the space between clothes and bag to fully warm, but once it does, its definitely warmer. I've done it both ways.

So to sum up the thread, if you pee you'll need less energy to stay warm. However, you also lose the heat previously invested. So there's no question that you lose heat in the short term, in the long term I think it would depend on metabolism if it keeps you warmer (moot point though since you can't hold it long term).

I'd still like to hear experiences though...next time I go camping in a cold place I'll be sure to pay more attention.

This would be a good mythbuster's myth. There's gotta be a reason it started in the first place.

Rekna

I don't think the peeing to stay warm myth is true. Here is the general equation for heat transfer:

Q = -hA(Ts – T)

Q is the amount of heat transferred, h is the material constant, A is the surface area, Ts is the temperature at the surface, and T is the outside temperature.

Thus the rate of heat loss is proportional to the amount surface area (aka your skin). The only way that peeing could change this rate is if it affected the material enough to change the heat constant. This is unlikely as the material is your skin and not the rest of your body. Your skin is the primary insulator for your body and what is inside it should not affect heat loss. Now if you drink a cold drink you will of course lower your body temperature.

This is the same for an empty house or a full house or an empty fridge or a full fridge. As pointed out earlier the difference between full and empty is how long it takes to reach the stable temperature.

Willravel

Peeing will warm you up the way vacuuming your car will help you go faster.

inBOIL

Peeing will warm you up if you're in a wetsuit.

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achillesheel

One other trick I learned from my camping years is to eat a candy bar right before you go to sleep (my favorite was Snickers), the energy your body spends digesting the sugar will help you stay warm through the night.

ratbastid

If I paint flames on the sides of my penis, will that make me pee faster?

Xerxys

Now this is just funny.

But seriously, who can explain then, the heightened bladder activity during cold weather? Peeing does not warm you up ... it KEEPS you warm.

Rekna

Sorry but the laws of thermodynamics run counter to this thought. All that matters is the material constant, the change in temperature between the two surfaces, and the surface area.

Why do you think crushed ice melts so much faster than the exact same volume of solid ice? It is because of the surface area.

HamiC

From personal experience...peeing when camping in cold weather does allow you to stay warmer. I am no thermodynamics guy, but I am guessing that you expend some amount of energy to heat the urine in your bladder to a constant temp. As it is no warmer than your core temp, you get no heat from it...you simply have to put heat energy into it. Get rid of it and you can use your finite thermal energy to heat the innards that remain.

As for losing more heat by stepping out of the tent for a moment, the transfer of heat between your body and a liquid is somewhat more efficient than between your body and air. Air is a poor conductor of heat. Also the time in the cold -- even if your bladder is pretty darn full -- is much less than the time your are likely to be stuck warming the excess urine.

On the sleeping bag front, I'd go with wool/synthetic socks and a wool/synthetic cap...and nothing in between. The big risk with clothes in a sleeping back is that they will trap moisture against your body (and the moisture will conduct the heat away more quickly). If you wear wool or synthetics, no worries. Cotton sucks (literally) the heat away.

On the plus side, going starkers -- especially when your sleeping bag is zipped together with someone else's -- has other advantages beyond heat retention.

Zeraph

What about silk? I often wear it for reasons you wouldn't guess.

Xerxys

^^ Your a tranny?

JamesB

I can personally attest that peeing helps make you feel warmer when you are cold.
I can also tell you with absolute certainty that sleeping naked in a sleeping bag is warmer.

I have spent many, many weeks sleeping in a winter bag at far below freezing and have tried almost every conceivable method to stay warm. Naked is best because of perspiration. But a good cotton liner is a must!

People kind of miss the mark with their peeing considerations. Yes, you lose the instantaneous heat that the urine bears, however, you are not longer expending energy to maintain the urine at your core body temp. which far out-weighs the singular loss of heat from the urine. Further, storing the urine will require the expenditure of energy for reasons of ionic concentrations, etc. that are quite energetically costly. Many more variables to consider than grade 10 thermodynamics.

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G5_Todd

you can use the urge to piss as an alarm clock too.....if you drink a full glass of water b4 bed you will wake up naturally about 8 hours later

---------- Post added at 12:43 PM ---------- Previous post was at 12:41 PM ----------

i have heard that sleeping naked in a sleeping bag keeps you warmer....but in my experience in the military it didnt help me.....

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Rekna

This is essentially the same problem as a full or empty fridge:

Refrigerator and power used, full or empty? - Yahoo! Answers
How to Maintain Your Refrigerator and Save Money - Associated Content
TreeHugger Tip: Tomm Stanley on Refrigerator Efficiency : TreeHugger
Get Better Efficiency from Your Empty Refrigerator
Similar questions with full refrigerator require energy cool empty

It is definitely possible that peeing will help keep you warm, however, the reason is not that your body no longer needs to heat up your bladder (same argument with open vs full fridge). Maybe there are other things that happen after you pee like your metabolism changes causing you to burn more energy and create more heat. Or maybe you drank cold liquid before going to bed and your bladder has not reached your core temperature. Or maybe it is all in your head. Once the pee reaches your core temperature peeing will not save you energy but will likely let you sleep more comfortably. So I say go ahead and pee.

Kingruv

Why the issue?
Pt1
Physiology:

Factors: Cold weather reduces sweating because of vascular constriction. Since the extremities are thinner compared to the core they of course cool first. The body is concentrating blood in the core. Since there are more nerve endings in the extremities you'll also sense this more readily. This is a self preservation mechanism and warns you by discomfort. Heat loss through the head, neck, face and eye sockets, as well as through breathing, increase loss. These all need to be mitigated by covering.

In addition to this, if you have been expending energy before sleep any sweating you've done will cause further cooling. Waste build-up in the blood exceeds in cold weather that of hot weather. The skin is able to flush (literally) through sweat, during warm weather providing ventilation directly to the limbs and core to some degree. Again the lungs through breathing helps cool the core some. As the core tries to retain more heat, the liver and kidneys continue working, filtering blood. The brain, if called on for concentration, signals the kidneys to reduce blood plasma of some water content. This in turn goes from the kidneys to the bladder for eliminating.

Now, to the likely why. Since there is some muscular contraction during cold weather and a higher production of urine, you are likely to feel the urgency sooner rather than later. The muscles around the pelvis contract along with the rest, putting more tension on the bladder.

This is a guess, but I think the heat loss issue is a time problem. As the bladder fills, the urine is warm. This warms the bladder which in turn radiates some heat outwards lending heat to veins returning from the legs where blood has cooled. The gain turns to loss over time though. When lying down and inactive, the body is allowed to divert more energy to the issue, again raising urine production. Getting out of the bag certainly doesn't help.

Pt 2
Consumption habits
Ideally, water which is at least warm is the best thing to drink during cold weather. Blood always needs more water for replacement. The first, highest priority for this is brain fluid. In a healthy person the most purified water becomes brain fluid which in turn becomes spinal fluid and passed on to the nerves. Anything that mitigates this such as alcohol, aspartame (Nutrasweet), caffeine, and a few other items, diminish the benefit from water combined with the above.
You might be surprised I mention aspartame. When aspartame is consumed, it chemically breaksdown into methanol which of course is poison to the body. In a healthy person, and since it is a somewhat small amount by episode, the liver is able to deal with it by changing it into formaldehyde, another poison, but a convertible waste the body can eliminate. This takes energy you already need for heat production. (do you get headaches when using foods or drinks with Nutrasweet? It's from the methanol.)
The effects of alcohol on this should well known enough I won't get into that.

I think caffeine is a mixed bag. It is a stimulant and has diuretic effect. On the other hand products such as chocolate and coffee can be ok and maybe beneficial as long as someone doesn't have a low threshold for side-effects. Achillies is right about the candy bar. Just don't pick something too sweet. Chocolate covered raisins and cashews are good. Because of the high fat content, it makes a prolonged burn during the night. Kind of like banking a fire before bed.

Drinking to make sure you don't sleep too long can be used beneficially. The problem I've had was getting into the habit to make sure I had a early morning call about 4, that as I've gotten older and don't need to get up super early, I forget at times and by force of habit still drink too late sometimes.

There have been plenty of times in bygone days, I have gotten on my knees with my bag pulled up to my shoulders to allow just enough room to hold a pee bottle without getting out in the really cold weather.
As to staying warm, prepping the ground under your bag goes along ways to helping this. (bury a few dry, softball sized rocks heated by campfire below your feet about 6 to 8 deep. If there are needles around, pad the area under your sleep area with them.)

As regards to wearing in a bag, I'm NOT a tranny and I do wear silk longhandles still at times. It was the defacto superthin underwear for waterfowl hunting before polypro. It won't keep you warm as wool if wet but otherwise it's as good. It's also lighter and thinner to pack, wash and dry and other issues pertaining to travel outside the country.

From the FOG (frackin old guy)

seamaiden

Okay...I'll admit, I have peed in my wet suit...and it did make me warmer, but basically I did it because I was 40 feet below the surface of the North Atlantic. And the nearest bathroom was a long swim and an even longer struggle out of my neoprene second skin.

Can't say I've ever noticed feeling warmer after peeing in a conventional manner.

GreyWolf

I've also peed in a wetsuit... it does work, and the natural flow of water through the suit dilutes the urine relatively quickly. It's not unsanitary. But a teakettle of warm water down the neck of the suit before you enter the water works better.

As for the refrigerator/empty house issue, there's a lot of confusion among the energy efficiency experts because they don't have consistent sets of assumptions (I worked in a related field for 15 years). The heat absorbing mass of a house (i.e. whether it's empty or full) has absolutely NO impact on the amount of energy required to heat a house over time. Thermal storage schemes take advantage of the COST of energy at different times, not the total amount of energy required. It's the same, and is governed by the surface area of the house, the efficiency of the thermal envelope, and the ambient weather conditions.

A refrigerator is the most efficient heater in almost every home that doesn't have a heat pump. It uses a heat pump (condensor & evaporator coils) to pump the heat from what you put inside it back into the kitchen. Relatively little energy is required to do this. You get the same effect by filling a fridge as you do with filling a house. You create thermal storage. A full fridge will stay cooler longer because of the cold (lack of heat) stored in the stuff in it. Overall, filling a refrigerator makes it consume more energy in pumping the heat back into the kitchen.

As for peeing when you're camping, most of the arguments here miss that fact that the human body is not a static one. It is working to maintain a thermal differential against the cold. The more mass you have, the lower your surface-to-volume ratio (and likely the higher your level of insultation). This equates to more efficient heat retention. The extra amount of urine in your bladder would be inconsequential in this equation... BUT peeing is like pouring hot water down the drain. You've expended energy in heating the water, and it's going right down the drain. In the case of urine, although you don't have to reheat anything (the mass is gone), you are losing some heat you've already generated. But given that the body is thermally dynamic, the actual loss is again likely inconsequential.

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Tesla

People often need to pee when it's cold, and that's not for no reason.
The inside of the body is shrinking to maintain heat, especially in the vital organs, and bladder gets under pressure of surrounding tissue, so for it to shrink it needs to expell urine inside it.
And because that whole process is instinctal, it is alright to think that peeing is not giving off as much energy as shrinking of internal organs is perserving.

---------- Post added at 11:55 PM ---------- Previous post was at 11:51 PM ----------

And in addition, blood vessels in extremities shrink too, so the heat doesn't go off as much in hands and legs. And I have read somewhere that more than 75% of heat loss is lost in extremities.

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Slims

Technically, when you pee you reduce your surface area because the skin around your abdomen will reduce in surface area relative to the quantity of material you have...released. Though it is a very, very small change peeing will reduce your surface area thus allowing you to better retain heat. Though the difference is probably too small to notice.


My proposal: Your body begins to shed fluid in cold weather because the cold causes blood vessels in your extremities to contract in order to better retain heat in your core. I don't know the mechanics, but it results in your kidneys excreting a larger volume of urine than would otherwise happen.



If you don't drink you will get dehydrated, which can contribute to your bodies susceptibility to hypothermia, etc. So oddly enough ensuring that you continue to pee by drinking water will help you remain warm

Even though drinking cold water when you are near hypothermia can be near unbearable.

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donmaytee

Put a wet-suit on, then pee.

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Tesla

You summed it up well ^^

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taurus

As someone who's spent a lot of time in the water, i will support and qualify that peeing in your wetsuit does warm you up (for a while) but the loss of body heat will eventually make you colder. So, if you want a little burst of warmth, do it but know it will be colder later! O, and make sure you don't pee in your dry suit.

Tesla

lol. And what about peeing on someone else? will that transfer your heat to him

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