Urine contains waste products-urea, salt, ketones. The more concentrated, the more products per milliliter. probably not a good idea not to eat excreta (even if you can see the undigested kernels of corn, it is a bad idea) and analogously, unwise to drink urine, cuz it will recycle the waste products, Urine is sterile, unless something nasty is going on between bladder and the great outdoors. In WWI, soldiers in the trenches took turn urinating on each others hands to salvage the lost heat. One could pee into a solar still and collect condensate for drinking purposes. NASA has some technology for recycling waste-http://www.ctv.ca/servlet/ArticleNews/story/CTVNews/20071021/nasa_urine_071021/20071021?hub=TopStories.
Nasa apparently uses reverse osmosis, which is kinda tricky for survival kit use http://www.freedrinkingwater.com/infocenter.htm

Uhm... I don't know how long you think an emergency will last. Let's call it 14 hours, for the sake of argument. I base that on having an approximately 13.5 hour "night" for both of us, less that first hour you spend blundering about thinking you are right next to the parking lot, but plus hour and half that you spend in the morning actually getting there.

Fishmode, if you are willing to conduct a test, from the moment you read this, for the next 14 hours, you are NOT to urinate. I hope you peed before you checked this.

Honestly, I don't think you can do it. I think your bladder will whine, complain, and eventually grab you by the nose and say point blank "look buddy, I'm full, I'm going to be emptied- your call how and where, but the when is going to be in the next sixty seconds." If it has been more than ten hours since your last pee, you are probably in trouble.

It seems to me that the sensible thing to consider in a survival situation is that you would want to hold your liquid past the initial urge, but not to the point of excessive discomfort or distress. Heat loss is a practical consideration, as is a full bladder will tend to diminish the production of urine by the kidneys slightly, thereby having some positive effect on reducing dehydration, but this is a marginal consideration at best.

On my first big hike in the Canadian fjords, I was able to refrain from defecating for three days with reasonable comfort. I don't know what benefit that was for me, other than conserving the TP, and possibly scaring a bear when I did finally seek relief. You can find a purpose in all things I guess.

The last thing I want if I come face to face with a bear is a full bladder.

Sue's Basic Survival Rules

1. Relieve yourself when you have to, at the earliest opportunity within reason. In a survival situation, conditions may deteriorate rapidly.

2. The water in your bottle won't help your mental or physical condition if it stays there. Drink!

3. Always carry a little food with you. Even if you don't eat it, you'll know you've got it, so you don't have to worry about THAT right now. You probably have other, more pressing problems. And if you don't have anyone to outrun, you can drop the honey-dipped granola bar and maybe the bear will stop and check it out. (Also read #1 again.)

Sue

You PEE to get rid of by-produts. I do not think any of you case to pee or not to pee is valid, cold or not. In peeing in cold weather you actually losing heat. You are not generating heat to keep you bladder warm. All the fluids going into you bladder are at body temp.
Also drinking you urine is bad because you just talking back into you body thing you have attempted to get rid of. It can tax you kidneys and cause renal failure. So Bear is STUPID in this case.
cheers

NO fluid reabsorption occures in the bladder but in the large intestine.

The way that I retained water in my body for up to 6 hours WITHOUT discomfort,,,,,,,,We would eat a couple of Fig Newtons every hour. After 6 hours, my eyeballs were yellow but I wasn't in discomfort and I could walk normally to the Head once the bird was secured.

And no, drinking urine is NOT a solution to dehydration. Keeping a wet bandanna around your throat and sucking on a pebble or button helps to ease the symptoms (at least psychologically speaking).

Back as a young scout winter camping, I always had to pee at 3am. I would lay there for 20 minutes trying the get up the courage to get out of my very warm bag and do the deed. I was always warmer after. You gotta go, go!

A trick from the Inuits and homeless is to keep a jar or jug handy and to do the deed while laying on your side. It isn't a hard trick to learn. Saves time and heat. Unfortunately the solution is not so clear or simple for the distaff campers.

A particularly game, adaptable, and flexible, lady claimed that it is doable using a little device called a "Lady-Jay", essentially a small funnel I think, but, despite my requests, I was not allowed to observe this evolution in any detail so I can't really testify as to how easy or practical this might be.

I had an old guy in our hunt camp one time explain to me that in the days before alarm clocks, having to get up to use the outhouse was how you woke yourself up in the morning.

This fellas English was poor and my French was worse but I think the way he said to do it was this; before going to bed when you absolutely had to get up early the next morning (e.g. to go hunting) you drank a lot of liquids, that way your body would not allow you the comfort of sleeping in.

This fellow was 76 years young and got up about 3 times a night, the best thing was that he added wood to the woodstove each time so our uninsulated camp was nice and warm at 4.30am when the rest of us got up.

Merry Christmas,

Mike