The risk factors for cardiovascular diseases increase further and further in the modern societies. One of the major risk factors is physical inactivity, which is even more pronounced during the winter months especially in countries with tempered climate. One step towards health prevention in winter, is to investigate the metabolic and cardiovascular effects of winter sports like alpine skiing and cross-country skiing, which could potentially fill the physical activity deficit during this problematic season. To estimate the efficiency of these two exercise modes, they have been compared to indoor cycling training, which could be seen as the gold standard of recreational sports. The oxygen uptake is one of those physiological parameters, which indicates the intensity and therefore the effectiveness of different exercises and sports. This book points out the eligibility of the mentioned sports and their different skiing styles/intensity levels, for health prevention.