Being that I happen to be one of those "sub-human freaks of nature" that never gets cold (Colorado and Montana lakes in a wetsuit, sleep with the windows open and heat off in our bedroom all year, only start really sleeping well when ice starts to form on my mustache), I only have suggestions.
What about trying a thin wetsuit inside your drysuit? Something like a Henderson Hyperstretch 3mm or other super stretch in the 2-3mm range. It should still provide the freedom of movement but may keep the heat trapped in better.
What about trying a thin wetsuit inside your drysuit? Something like a Henderson Hyperstretch 3mm or other super stretch in the 2-3mm range. It should still provide the freedom of movement but may keep the heat trapped in better.