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CoreLoop™
heat mapping

Close
the loop

Why your hands go cold first

When you get cold, your body protects its core first. It narrows the blood vessels in your hands and feet and keeps warm blood close to your heart and organs. That is why your fingers and toes go numb long before the rest of you feels cold.

CoreLoop™ heat mapping is how we decide where every heat panel goes. We heat the core where blood runs close to the surface, so your body has no reason to cut off your hands and feet. Then we close the loop with heated gloves and socks at the two places that cool first.

Core

Vests and jackets heat the core where blood runs close to the surface: the chest, collar, back and hand pockets, depending on the piece. Every zone we list matches the factory heat-zone diagram for that product.

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Hands

Fingers are the end of the loop, so they cool first. Belay gloves add heat across the back of the hand and down the fingers, and stay slim enough to tie a knot.

Shop Belay gloves

Feet

Toes are the other end of the loop. Switchback socks heat under and over the toes, with the battery up on the calf where it stays out of your boot.

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What the research says

Brajkovic and Ducharme (2002) found that warming the torso kept fingers warm and nimble better than heating the hands directly, in 3-hour tests at −25°C (−13°F). A companion study by the same team linked the body's heat content to finger temperature and dexterity in the cold.

CoreLoop™ heat mapping puts that idea into practice: heat the core first, then add heat at the hands and feet, where the loop ends.

  1. Brajkovic D, Ducharme MB. Maintaining finger dexterity in the cold: a comparison of passive, direct and indirect hand heating methods. NATO RTO Human Factors and Medicine Panel symposium, Blowing Hot and Cold, 2002 (DTIC ADP012428). Read the source
  2. Brajkovic D, Ducharme MB, Frim J. Relationship between body heat content and finger temperature during cold exposure. Journal of Applied Physiology, 2001;90(6):2445-52. Read the source

CoreLoop™ is our name for how we place heat in our gear. The studies tested heated clothing in a lab, not our products, and how warm you stay depends on your layers, how active you are and the weather. The heat zones we list for each product come from the factory heat-zone diagrams.

Warm the core.
Close the loop.

Scroll to see how heat moves through the loop.

  1. Your body protects the coreIn the cold, blood is pulled back from your hands and feet to keep your core warm.
  2. We heat where blood runs closePanels sit on the chest, collar and back, where warmth spreads furthest.
  3. Warm blood travels the loopA warm core lets your body keep blood flowing out to your fingers and toes.
  4. Close the loopGloves and socks add heat where the loop ends.

Built on research by Brajkovic and Ducharme (2002), which found that warming the torso kept fingers warm and nimble better than heating the hands directly, in 3-hour tests at −25°C (−13°F).

Build your loop

Pair a core layer with gloves and socks. Any 2 pieces save 15%, all 3 save 25%.

  • Core + Hands: any 2 pieces save 15%
  • Full Loop: any 3 pieces save 25%
  • Mix sizes, colours and products. The saving applies automatically at checkout.