Why do they wake at 3am? And how to get them back to sleep?

My own experience is that people usually wake because they get cold around the head and shoulders. 3am is when the outside temperature drops right down, and the body finishes digesting dinner – which reduces the heat the body produces. Older bodies produce less heat anyway. Insulating blankets trap heat but don’t produce it. Warming people up often sends them back to sleep.

It’s worst for those who sleep with their head under a window, or next to a not-too-well insulated wall with cold on the other side, or (like me) next to a foot-thick stone wall that never heats up.

Ways to help:
An electric blanket on a timer to come on at 3 am.
A warm bonnet, kerchief or cap (just like in ‘the night before Christmas’).
A comfortable bed jacket that keeps you warm around the shoulders (even a soft pullover).
If you have to get up, a heat pack and an extra blanket.
I‘m considering a quilt hung vertically on the wall behind the bed head, to insulate the wall better.

I hope this helps. It’s taken me a long time to figure out!