Re:cold in sleeping bag.

1. The sleeping bag insulates, does not "heat" - you have to provide the heat - this means your body has to be warm when you get in. I have a hot meal or drink, take a 5-minute evining fast walk, strip down to light base layer, hop in and stuff extra clothing in the bag too. When I get the bag warm then I put on more clothes as the evening cools.

2. Once your bag is warm, keep drafts out. This means a draft collar for the temperatures you encountered. A draft collar lets you cinch around your neck even if you do not totally cinch up the hood. The zipper draft tube is important too. I always am warmer with the zipper to my front (I am a side sleeper).

3. As the night wears on, your body has to keep pumping out heat. This means enough food at night - be sure to get about a thrid of the meal as fat - fats last longer.

4. There is no insulation where your body compresses the bag. This is the ground heat loss problem. At a minimum take a 2-3 foot long z-rest piece and put under your shoulders and hips.

5. It is my experience that if you have to pee at night, it is best to quickly get out and do this. A full blader makes me cold.

6. I sleep in a fleece balaclava. It is amazing how much warmer I am with this little 3-oz. addition. I also have a detatchable down hood on my winter parka - I take this sometimes and it really adds about 5-degrees warmth.

7. Feet need to stay warm - start with no socks and put them on later if it gets cold. Like the down hood, a light pair of down booties helps a lot.