Temperature plays an important role in sports - regarding both the athlete's performance and health. However, until now, these effects, e.g. thermoregulatory mechanisms as well as the variations of body temperature during physical exertion have barely been considered. This book presents studies and results which prove that cold application has a positive influence on the athlete's performance and regeneration ability. Based on the results of international studies, and considering the control mechanisms and principles of thermoregulation, the effects of cold application should be utilized in training and competition.