Upstairs Human introduced me to a wonderful device: the heating pad. I curl up in her bed and the pad makes it warmer for me. I get in the bed when UH gets out, so the heating pad is usually off when I get on it, but this time UH turned it on low. It got a little hot, so I left.
Some sick kitties are too sick to get up when they get too hot, so humans should be careful when sharing their heating pads. A hot water bottle is probably a better idea. If you want to pamper a sick or older kitty, however, you can buy us a heated bed or a pad just for kitties. Heated cabins will keep outdoor kitties really warm, especially if your area is cold.
It pays to be careful, no matter what.