Taking competitors through the frigid Arctic, the Polar Circle Marathon is one of the harshest races in the world. Even the most experienced runners have to make concessions to the unforgiving environment.
When the wind cuts like a razor and the temperature drops below freezing, regular running attire won't cut it. Officials suggest a minimum of three layers to keep warm: a base layer that wicks sweat from the body, a middle layer for insulation and a top layer to protect against the elements. Cotton is a poor choice, however—it won't keep you warm enough and can chafe your skin while you run.
You'll also need several layers of gloves and special shoes with soles that can stick to the slippery icy surface. Ski masks and scarves with holes for the mouth and nose are available at signup, but anything covering your face will require frequent de-icing.
Dehydration is an issue in any race, and water is supplied every five kilometers along the route. (Select stations also offer a warm elderflower cordial). But in this marathon, frostbite is the paramount concern: With temperatures hovering around 25 degrees Fahrenheit in town and dipping below 5 degrees on the route itself, runners must cover any exposed skin and continually check for tingling, numbness and blisters. (Frequently flexing your face muscles and fingers can help keep blood flowing to these areas.) They're also discouraged from showering directly before the race, as the skin's natural oils provide a barrier to the cold.
You'll need fresh clothing, energy bars, electrolyte-heavy drinks and other essentials that can be stored at the 10-, 21-, and 30-kilometer mark. If you need an immediate energy boost, though, pack food in a bag inside your jacket. (Your body heat will help keep it from freezing).
And bring all your gear with you from home: You won't find a sporting goods shop in the remote town of Kangerlussuaq, population 499.