I can endure the coldness by grace of two underwear this year. One is new material, heattech. Heattech is developed by UNIQLO, one of clothing makers. Clothing of heattech is very warm. It was sold few years ago and underwear or clothing of heattech became a big seller in Japan. I bought some heattech items this year.
In case of my room, it is very cold in winter. Especially the room isn't heated at night when I sleep. So the coldness is out of ordinary. However, when I wear heattech underwear, I can sleep well.
Another useful item is Haramaki 腹巻き. It is traditional thermal underwear and it has been used for men, especially for middle age or old men. It has not been cool for a long time. However, young women use now as one of thermal underwear. It is colorful and fashionable. Normal haramaki is made of wool. However, since close of haramaki is innovated, we can wear it under clothing. When I go out wearing it in cold day, it is very warm. Of course, there is heattech haramaki and it is so useful.
New technology and traditional underwear is essential for me in this winter.