• climate
• public health
• weather

“Whoever would study medicine aright must learn of the following subjects. First he must consider the effect of each of the seasons of the year and the differences between them. Secondly he must study the warm and the cold winds, both those which are common to every country and those peculiar to a particular locality....”
 Hippocrates, “Airs, Waters, Places”, 400 bc¹

“As important as the overall tendency toward global warming may be to human health, the effects of the extreme and anomalous weather that accompany it be even more profound”
 Paul R Epstein, 2002²

Many texts concerning epidemiology and public health, especially those on health matters related to environmental factors, start by quoting words written by Hippocrates more than 2000 years ago. As we see in the quotation above, this wise Greek doctor considered seasonal changes as fundamental factors in the explanation of health phenomena occurrence. Twenty four centuries later this matter still creates great interest not only among researchers and health professionals, but also among decision makers and the general population. One of the main reasons for this is the growing worry concerning the potential impact on health of an increase of ambient temperature because of the process of “global warming”.

The relation between environmental temperature and health has been known for a very long time. Various diseases and disorders such as heat stroke and hypothermia are directly linked with temperature extremes. Furthermore, the results of a number of investigations suggest that the relation between mortality and ambient temperature appears graphically as a “U” or “V” shape, with mortality rates lower on days in which …