It's not that I'm impervious to cold or anything, but I am always amazed at the way my sister layers clothing in the winter, like she lives in the Arctic (she lives in Maryland). She wears at least three items which would count as "outerwear" and when she strips those off and only noticeably has on a sweater or three, I know that she still has thermal underwear underneath. I have a thing, the same thing that happens when I wear a choker necklace or a turtleneck, where I get a little attack of claustrophobia when I try to wear long underwear or anything else that's binding and heavy. So I'd rather be cold. But now, using a fabric that sounds a lot like the stuff used to make Stay Cool suits, Wacoal has introduced a line of lingerie that warms you on cold days without the traditional bulk. The Kaiteki Navi line is coated with crystals that melt when your body is warm, and absorb the heat. When your body cools, the crystals solidify and release the warmth. And while it could be that this particular underwear model is so skinny that it just doesn't show, the fabric appears to be thin and lightweight, like underwear should be.

I believe this is in Japan only, at least for now, but Wacoal is very popular all over the world, so if it takes off in Japan, should be seen much more globally soon. I hope so because Wacoal makes unbelievable bras that make your clothes look much better because you're tucked in all the right ways. They'd be even nicer in winter, if they kept you extra warm as well. The KN line comes in t-shirts, camisoles, bras, panties, and what looks to be something you'd call shapewear (please don't say girdle, that sounds so ugly).

From Nikkei (subscription required for full article).