We’ve all felt cold from time to time, but unless you ignore your body’s natural reaction to bundle up when it gets too cold, then you’ve never felt the effects of hypothermia. Hypothermia is a medical emergency where body temperature drops dangerously low because the body loses heat faster than it produces it. James Appleton, three-time champion of the Tough Guy race (the UK’s equivalent of the Tough Mudder race) shows us what experiencing hypothermia really looks like.

As a person's body temperature drops below 90 degrees Fahrenheit, the hypothermia victim’s heart, nervous system, and major organs begin to malfunction. Symptoms of hypothermia include uncontrollable shivering, dizziness, hunger, nausea, rapid breathing, trouble speaking, confusion, lack of coordination, fatigue, and increased heart rate. If hypothermia is left untreated for too long it can result in the failure of the heart and respiratory system, as well as death.

According to the Centers for Disease Control and Prevention, a total of 16,911 deaths in the United States between 1999 and 2011 were attributed to exposure to excessive natural cold. The highest yearly total of hypothermia-related deaths (1,536) occurred in 2010. Hypothermia can also result in other cold-related injuries, such as the freezing of body tissues (frostbite) and the decay/death of tissue resulting from an interruption in blood flow (gangrene).