They say it takes some training. And there can be risks, like running when your feet are too cold to feel if you get injured.

VOA: special.2010.02.03

You can feel something cooling off right. I mean simple examples of these happen when you you know, if you buy cold or hot packs.

可以立即反应的东西,你可以感到有的东西会冷却，对吧？,我是说，举个简单的例子。

麻省理工公开课 - 热力学与动力学课程节选