Within a few decades, the science of sleep has undergone a dramatic change from being a subject that interested merely a minority, to becoming a widely discussed issue due to its medical consequences. The relevance of sleep disorders is not only based on its high prevalence (i.e., 4-6% for Obstructive Sleep Apnea, 2-3% for clinically relevant Restless Legs Syndrome, 8-10% for chronic insomnia, etc), but also on the increased cardiovascular and neurological morbidity. On the other hand, sleep disorders deteriorate the quality of life and carry on undoubted work-relates consequences as well as an increased risk of accidents.

Their impact on public health is not exclusively due to the disorders occurring during sleep, but also to issues more related to the modern way of life. Hence, a significant part of the population exposes itself, as a result of a particular life style, to a daily schedule that results in insufficient sleep time. Such has metabolic consequences with an increase in obesity and metabolic syndrome. Ultimately, such a life style increases the cardiovascular risk and reduces life expectancy. 

The question is why, being sleep disorders epidemiologically so relevant, has the interest in the scientific study of sleep existed only for a few decades? The answer is probably related to the way in which modern medicine considered for a long time the function of sleep: Initially, sleep was understood as the absence of wakefulness and accordingly, the pathophysiology of any existing condition would not change during wake or during sleep. However, the finding of disorders that occurred exclusively during sleep, such as sleep apnea, reinforced the interest to understand the influence of sleep and wake states on biological functions. Furthermore, any future progress in research of sleep disorders will be possible only if it is associated to a progress in parallel of Neurobiology.

Eightteen years have passed since, in 2000, the Fundación Ramón Areces organized their first Symposium in Madrid on "Neurobiology and Sleep Disorders". Since then, progress in areas such as Genetics, Neurobiology, or on the metabolic and systemic consequences of sleep disorders has been considerable. As a result, Sleep Medicine has emerged as a field of knowledge characterized by its multidisciplinary clinical nature that has marked consequences on various areas of health ranging form neuropsychology to systemic disorders (hypertension, etc.). The object of this new edition of the International Symposium will be to discuss, aided by several of the world´s leading experts, the current state of our knowledge in the science of sleep and to outline the main lines of directions for research in the coming years.