Training in a cold environment can place unique stresses on the body. Although frostbite and hypothermia are the classic cold weather sports injuries, fatigue, dehydration, and bronchospasm can also occur frequently in cold weather.

At the beginning of a run, clothing insulation and exercise metabolism are sufficient to maintain the athlete's body temperature in the cold. As fatigue sets in and muscle activity slows, body heat production decreases. As the core body temperature cools, the individual becomes even more fatigued and less capable of generating heat. Wind chill and moist clothing can accelerate cooling through convection and evaporation.

When exercising in the cold, do not overdress. This causes the body to become hot and initiate sweating. As the sweat soaks through the clothing, evaporation rapidly removes heat from the body into the environment. Clothing that transmits moisture away from the body may be protective if an outer wind-resistant layer decreases heat loss. However, this wind-resistant layer must retain the same transmission capabilities, otherwise clothing will still become moist.

Tight-fitting clothing may produce constriction, which hinders blood circulation and lessens the benefit of heat-retaining air insulation. Clothes that decrease the amount of surface area exposed may decrease frostbite risk. Mittens are more protective than gloves, since gloves have greater surface area and prevent air from circulating between fingers. Up to 80% of total body heat loss occurs through exposed head and neck areas.

Dehydration in the cold occurs owing to unperceived loss of fluid with inadequate intake. In cold, dry weather, large quantities of fluid are lost through exhalation. Cold weather also dulls the thirst response to dehydration. Additionally, the volume of perspiration loss may not be appreciated because of the voluminous clothing.

In cold weather, inspired air must be warmed and humidified by the body. In cold conditions, the air cannot fully be warmed and humidified. Reactive bronchospasm causing difficulty breathing and coughing may be quite problematic, especially for those with exercise-induced asthma, in addition to increased mucus production for 12-24 hours after the exposure occurs. Prophylactically inhaled bronchodilators such as albuterol can be helpful for these problems.

Dress right, stay hydrated, see your doctor if you are having breathing problems, and enjoy your cold weather training!

Stuart Willick, M.D. will be heading up the medical support and response teams as Medical Director. Dr. Willick comes to this inaugural Salt Lake City Marathon with an impressive background and credentials. Currently an Associate Professor in Physical Medicine and Rehabilitation at the University of Utah School of Medicine, he has a long history of sporting involvement. He served as the Medical Director for the Paralympic Village Clinic, Assistant Medical Director for the Olympic Village Clinic, and was the Event Physician for the World Cup Bobsled and Luge in 2002. He was also the Director of Musculoskeletal Services for the 2002 Winter Olympics and Paralympics. In addition to serving on the medical staff of the Chicago Marathon and the Chicago Triathlon he has been the event physician at numerous skiing, sledge hockey football and other sporting events over the years.