I had stage 2 hypothermia combined with severe dehydration several years back from a bad stomach bug. I lost 25 pounds of water weight and my temp was 93 degrees. It took me about 2 weeks to fully recover after the bug was gone. This illness had nothing to do with backpacking, but after that I don't play games with keeping warm and hydrated. I don't care if I have to carry a couple of extra pounds in my backpack, it ain't worth it to be on the stupid side of lightweight.