It’s cold outside!

After several days of snow, you’re itching to get out of the house. The skies are finally clear, so you call some friends and the three of you head outside for a walk. A teeth-chattering half mile later, you notice one friend is starting to slur her words a little. You look at her and realize she’s no longer shivering.

It’s time to get inside. Experts say the symptoms your friend is experiencing could indicate hypothermia. This is a medical emergency that happens when someone’s body temperature falls below 95° F – down from the average 98.6° F – because the body is losing heat faster than it can produce it.

Other symptoms of hypothermia include weak pulse, clumsiness, drowsiness and memory loss. Prevent hypothermia before it sets in by following this advice from experts.

Before you head out

Wintertime is “not the time to be a slave to fashion,” Mark Cichon, an emergency physician and chair of the Department of Emergency Medicine at Loyola University Chicago said. “Just stay warm.”

He recommends wearing a winter hat and protecting your hands with mittens or gloves to help keep body heat from escaping. And don’t forget to wear boots.

“You can always take layers off and put layers on, which will help maintain temperature,” Cichon said. “You don’t have to have a single, really heavy coat on when you can put on different layers to maintain the integrity of the warmth that you’re producing around you.”

Other ways you can prepare your body for frigid temperatures include making sure you’re hydrated and well-rested, says Gary Zimmer, a Conshohocken, PA-based doctor and member of the American College of Emergency Physicians. And eat a hearty meal: The body uses more calories when it’s cold.

Avoid smoking and alcohol use, which can hinder blood circulation.