High altitude is one of the most challenging environments for the human body. This is mostly because, due to low atmospheric pressure, the amount of available oxygen is much less than at lower altitudes. This environment represents a unique natural laboratory for biomedical research, which has raised increasing interest over the years, both from a medical and a scientific view point, for several reasons.
The massive development of tourism and sport activities in mountain areas implies that millions of people are periodically exposed for relatively short periods of time to altitudes above 2500 m. Such acute exposure to high altitude is associated with important changes in cardiovascular regulation that, although representing a kind of “natural” response to high altitude hypoxia, may in some cases become deleterious or “maladaptive”, giving rise to definite pathological conditions (Acute Mountain Sickness, High Altitude Pulmonary Edema and High Altitude Cerebral Edema). The underlying mechanisms are still not clear but these conditions may affect the performance and well being of affected individuals and, if not promptly and adequately treated, may even lead to death.
Even less is known on the effects of high altitude exposure in patients with chronic health disorders, including cardiovascular diseases such as hypertension, coronary heart disease or heart failure. This is not irrelevant since many of these patients maintain active lifestyle and may require advice on their safety when exposed to high altitude and on the possible treatment modifications in this condition. Unfortunately, as yet no evidence based recommendations exist nor can be issued in this regard.
The physiologic and pathophysiologic responses to hypoxia associated with high-altitude exposure can also be viewed as an experimental model for the study of chronic and disabling diseases characterized by decreased oxygen availability for tissues, such as heart failure (in particular if combined with chronic obstructive pulmonary disease), obstructive sleep apnea syndrome and lung diseases, as well as pulmonary and systemic arterial hypertension.
The HIGHCARE (HIGH altitude CArdiovascular REsearch) is an ongoing scientific international project that involves a series of multidisciplinary studies performed at high altitude, The HIGHCARE project aims to investigate the mechanisms of a number of cardiovascular and non cardiovascular changes induced by exposure to high altitude hypobaric hypoxia, along with the evaluation of the effects of pharmacological and non-pharmacological interventions applied in these conditions.
So far seven expeditions have taken place – five on the Italian Alps (HIGHCARE – ALPS, in 2003, 2004, 2005, 2006, 2010), one in the Himalaya (HIGHCARE – HIMALAYA, in 2008), on the south Nepal slopes of Mount Everest, and the last was located in the Peruvian Andes (HIGHCARE – ANDES 2012).