[Mountain medicine - an introduction. I].

Tourism to high-altitude areas is increasingly popular even from low-lying regions such as Denmark. Mountain sports include skiing, mountaineering, and ski touring. The young, elderly and at-risk individuals with pre-existing illnesses engage in recreational mountain activities. Thus, risk assessment and counselling regarding altitude exposure is increasingly relevant to all healthcare providers. In this first article of two in a review series, we summarize the state of the art of altitude physiology, alpine dangers and avalanches, and medical aspects of the increased UV-exposure at altitude.