My back is cold on a hot day. It's too uncomfortable to use a hot water bottle! What is the reason? Thank you!

I think I have a cold. Even in summer, we should pay attention to keep warm, especially for women. Sometimes blowing air conditioning makes my feet feel as cold as winter. There is also a kind of pillow, which can not only keep warm, but also adjust the temperature. Unlike the traditional hot water bottle, it can be washed by water washing machine without disassembly. It's a Naber brand. It can be used at home and in the office. You can consider replacing the hot water bottle, which is cumbersome and troublesome, and the heat preservation time is short. Naber is a clothing brand. This year, an intelligent warm suit was introduced, which can also adjust the temperature so that people are no longer cold in winter and prevent frostbite.