[Physical activity and training at high altitude]

In recent years there has been a growing interest in the effects of high altitudes on the human body. High altitudes are being frequented by more and more people for sport and leisure pursuits, and are increasingly being used both as a training environment and for investigating the healthy body in hypoxic conditions. During the ascent from sea level, atmospheric pressure and partial oxygen pressure decrease, humidity and temperature decrease, and radiation is elevated. The altitudes at which physiological changes and clinical symptoms occur are not constant, but variations may usually appear above 2300-2800 meters. There is a wide variability of reactions to low oxygen in the air inhaled. The physiological parameters during both rest and physical activity at high altitudes are different from those at sea level, and the differences are reflected in concomitant changes in attitude and behavior. Research into altitude as a training environment that could improve athletic endurance and performance has grown in the last decade, with the development of a number of new training methods, such as "Living High--Training Low" and "Training High--Living Low". These have contributed to an improvement of performance in a significant number of athletes. This article will demonstrate the impact and possible dangers of physical activity at high altitude, and will present the current knowledge and methods of altitude training. This article reviews the influence of low air and oxygen pressure on athletic performance. Recommendations are presented regarding physical activity at high altitude and nutritional support.