There is a double belief that causes health authorities to hold back from vigorously promoting healthy behaviours. The first is linked to the idea that there is a trade off between the quantity and the quality of life. Why increase the individual length of life if it is at the price of the quality of the years lived. But what do we mean by the quality of the years lived? Happiness or well being? This approach is considered too wide by the important literature devoted to this question in the field of health and social science. Experts in this field prefer to limit quality of life to what is conventionally called Health related Quality of Life (HRQoL). The key elements are, then, pain and self perceived symptoms, functional status and disability and perceived …