This tip comes from extreme athlete, cold exposure expert, and NYT bestselling author of The Wim Hof Method Wim Hof. Being able to control your breath is essential to creating heat from the inside out.
With this breathing exercise, Hof says you’ll be able to warm your body without an external heat source. “With practice, you will feel the heat ﬂowing down from your neck to your whole body,” he writes. “Everybody is different, but with practice, you will feel the heat coming from inside your body.”