I just returned from an overnight backpacking trip near the rim of sycamore canyon in Arizona. The overnight low was 28*F. I was with a group and we stayed up late and I was nodding off and trying to keep myself awake. Eventually I staggered over to my hammock to sleep. I brought along three underquilts, mostly for demo purposes, and to test the lower limits of these quilts. I had my full-length IX underquilt, a DIY PLUQ, and my new crowsnest from stormcrow. I started with the IX, which lasted about 10 minutes. It was down in the low 30s at that point. I decided to jump right to the crowsnest as I've spent cold nights in a hammock before and I didn't want to mess with it out in the field. I was surprised at how cold I was so I pulled all three UQ and an insert to my burrow top quilt and I slowly started heating up.
This is odd for me because I've taken just the burrow and crowsnest down to 15*F before. It got me thinking about other tips on staying warm. I think what happened in my case was that my body was slowing down for the night and not producing as much heat. I wondered if I had gone to bed when I was more active I would have been okay.
I know exercising a little before getting into bed has been suggested, along with eating something so your body has something to burn. I don't think 28*F is all that cold for the gear I brought--I don't fault them. I'm more curious about the situation I put myself in if that contributed to the chill.
What other tips are out there to get your body prepped for cold weather sleeping? I'm not talking about additions like hot water bottles; but rather how to best prep your body before hitting the sack. I think I wore my body down that night, which led to a difficult night.