You've just cleaned your teeth, you're feeling minty fresh and ready to climb into bed. You take a sip of water, but the ...

It happens more often than you realize. You’re drifting off into sleep, but suddenly, you feel an unexplained chill. You grab for another blanket, pull your hoodie tighter or tuck your feet in deeper.

Medically reviewed by Erika Prouty, PharmD B12 deficiency can cause increased sensitivity to cold due to its link with anemia ...