I have bladder incontinence and I like to camp sometimes. My friends tells me if I’m camping in ten degree below weather with a down sleeping bag and I have a bladder accident at night, I will probably die. What about a synthetic bag?
I presume theyre talking about an accident that saturates the sleeping bag itself - if some other kind of precaution is used (and I confess, I know little about these) to contain the spillage and prevent it substantially wetting the bag, I’d have thought it wouldn’t be a serious problem.
A synthetic bag will keep you warm even when wet. The disadvantage is that they weigh more than similarly insulating down bags. Other than that you get what you pay for.
Certainly a soaked down sleeping bag doesn’t insulate very well, but this sounds a bit extreme to me. The part of the bag above your body insulates from the air, but I question how wet it would get. The bag under your body doesn’t insulate much at all, being compressed by your weight. It’s the ground pad under you that insulates you from the ground, and it wouldn’t be affected much by wetness. While any significant amount of moisture in the bag is undesirable, I doubt that wetness of the bag and pad below you would lead to death.
Practically speaking though, wouldn’t the problem be avoided by wearing an incontinence diaper?
Down does not insulate well when wet, but having a bladder accident won’t soak the bag enough to endanger your life. The biggest advantages of down are lighter weight for the same amount of loft, and longer life. Synthetic bags stay warmer when wet, but they are heavier and they lose their loft over time.
If you’re car camping and don’t do so frequently, a synthetic bag makes more sense. If you’re backpacking and plan on doing so a lot, IMO it doesn’t make sense to buy a synthetic -20 bag.
I assume you’ll have dry clothes to change into. That’s a bad night but not death. Synthetic bag is probably the way to go anyway.
The real problem that might arise is putting the still warm and wet sleeping bag into a compression bag resulting the sleeping bag becoming more uniformly wet with every night.
If the daytime temps stay below freezing you could let the sleeping bag freeze before packing it. But if they don’t you’ll quite quickly end up with a pretty much useless sleeping bag if your out for more than a couple of nights.
The solution is a vapor liner inside the bag, a pretty standard item for serious cold weather camping. Because there’s a bigger problem than the one you have when it comes to moisture in sleeping bags in cold weather,
And it’s the same problem with boots and insulating outerwear in those conditions. You can try to control it but no matter how cold it is your body is going to lose moisture through your skin (remember dehydration is as big a problem in cold weather as it is in hot. You can watch the water leaving your body every time you exhale (real fun when you’ve got a mustache/beard, facial icicles!) When it gets to that last layer between you and the cold it’s (most likely) going to condense faster than it evaporates/sublimates.
Even in moderately cold weather not wearing vapor barrier socks (preferably with wicking/wool/fibers that don’t lose their insulating abilities when damp liner socks) means cold feet sometime during any winter hike. Been there, done that, on even relatively short day hikes. 
<sad and COLD smiley!
CMC +fnord!
Down is a poor insulator when wet. Some of the modern synthetics are approaching it in weight.
I have a couple (different weights) backside brand bags that I prefer to my old down bag. They live up to thier temperature ratings, and maybe even a bit cooler.
http://allsleepingbags.com/the_backside.html
One VERY important thing: Nothing insulates very well with your weight compressing it. Insulating from the cold ground is a significant problem. Air matresses do a poor job, as there is nothing to block air circulation (convection currents) inside the mattress. Thermarest self-inflating pads are the best solution I have found, both from a warmth and cushioning standpoint. They are a bit expensive and worth every penny.
To make a down filled sleeping bag, do they kill the goose?
Yes, but that’s a by-product of killing geese to eat. Much of the down sold in the US comes from China, where they eat goose about as much as we eat chicken.
It’s presumably more humane to pluck them after they’ve been killed - it is possible to pluck live geese, but it’s apparently a terrible ordeal for the bird.
Is wearing a diaper not an option? I can’t imagine carrying around subsequently sleeping in a urine-soaked bag. In any case, I would go with a synthetic bag just to be safe; as others noted synthetics still insulate when wet.
Ok, long time lurker here, with a lot of sleeping bag experience in all seasons.
Down is not only a bad insulator when wet, due to evaporation it will probably pull heat out of you and into the environment.
Synthetics, from intimate and miserable personal experience, are little better despite everything you hear. The difference is that down plumules wet out and matt together into something like paper mache, whereas synthetics retain a certain amount of loft. A synthetic bag will still insulate somewhat but will also be losing great amounts of heat energy due to evaporation. A wet sleeping bag of either kind is probably less warm than just putting all your clothes on. Consider bringing an extra bag.
In sub zero temperatures I would put any wet sleeping bag aside, put all my clothes on, and either cozy up to a heat source and/or start moving to keep warm. In summer or milder temperatures you may be able to dry out the sleeping bag with body heat over a couple nights.
I recommend a good inflatable insulating pad such as a thick Thermarest or Downmat. These are essentially impervious to moisture and and will insulate no matter how wet they get.
Vapour barrier liners provide waterproof protection inside your sleeping bag, they would be very sweaty in summer temperatures, but are fine for winter. You would still want to clean up with a towel or something absorbent however after an accident. They have the added advantage of keeping your bag clean and dry (bags get damp just from body moisture) and increase the effective insulation value.
For summer I would recommend a two part system with a sacrificial blanket on the bottom to take most of the punishment, withthe sleeping bag on top.
Finally, if you are male (not so easy for women), and your incontinence is somewhat manageable, a pee bottle for use inside your sleeping bag is a wonderful convenience once you get used to it. Urination is a lot easier if you don’t have to get out of your bag in the cold night. A little daunting at first but once you’ve tried it…