ON THE TRAIL
Lose layers. If you overdress at the trailhead, you’ll soon be sweaty. Instead, do jumping jacks or jog in place so you’re not chilled for the first 10 minutes.
Stay dry. In extreme cold (below zero), manage your layers and pace with this legendary Arctic adage in mind: You sweat, you die.
Keep layers handy. You’ll take them on and off frequently. When you’re not wearing a hat or gloves, stow them in pockets, down your shirt, or clipped to a shoulder strap. Stash your puffy jacket and a shell in the top of your pack.
Breathe through your nose. In temps below 20°F, some hikers experience chest pain from cold air. Inhale through your nose and the air will warm up before it hits your lungs.
Take short breaks. Maintain the body heat you’ve already generated by resting briefly (and more frequently if needed). At breaks, put on an extra layer right away–don’t wait until you’re chilled.
Eat fast. Stash snacks in each pocket of your puffy jacket, so that when you put it on during breaks you can refuel without digging around. Keep energy bars from freezing by storing them with a hot-water bottle or hand warmer.
Sit on your pack. Conserve energy during rest stops: Sit on your pack (read: insulation) with your back to the wind.
Keep your feet warm. Prone to cold toes? Cut a square from a closed-cell foam pad (light and cheap) to insulate your feet during breaks. Always change into dry socks if your feet get sweaty.
Use chemical hand warmers. These have myriad uses beyond saving cold digits: Stuff them in interior pockets to increase core temp; pre-warm a sleeping bag by tossing one in an hour before bed; thaw frozen boots in the morning; boost stove output by taping one to the canister.