The 29-year-old royal, who will race with a team of injured British servicemen and women against groups from the United States and the Commonwealth, spent around 20 hours in a cold chamber where he was subjected to temperatures of -35 Celsius (-31 Fahrenheit), with wind speeds of 45 miles per hour.
Alongside four teammates - all amputees who lost limbs after sustaining injuries in Afghanistan - Harry tested the clothing he will wear on the 200-mile (320-kilometer) expedition and learned how to avoid frostbite.
When asked Tuesday what the worst part of his overnight experience was, Harry joked: "Going in."