Exercising in cold weather is a fact of life for many athletes. For some, low temperatures are an unwelcome element in competitions or off-season training. For other athletes, including Nordic skiers and ice skaters, cold weather is an essential element of the sport. Regardless of its specific role in a sport, cold weather can profoundly affect the physiological responses to exercise. In some cases, it can present a significant health risk. Coaches and trainers must be prepared to help their athletes overcome the hazards associated with cold.