This Research Topic is the second volume of the “Cardiovascular Adaptation to Extreme Environment”. Please see the first volume here
Extreme physiological conditions can be environmental, such as hypobaric (space or altitude) and hyperbaric (diving) ones or situational, like strenuous exercise. In all these conditions, the human body needs to respond acutely in order to maintain own homeostasis and, whether the same condition repeats continuously, to adapt with deep changes in own systemic physiology. This is important to avoid allostatic load that may induce a deficiency of the systems designated to stress response until the extrema ratio of tissue damage.
The cardiovascular system has been one of the main human systems studied to assess the acute response and the chronic adaptation to extreme conditions. There are different concepts to define its response. For example, it is known the term “heart fatigue”, defined as the transitory cardiac dysfunction following strenuous exercise, or “cardiac damage” when an increase in troponin and/or brain natriuretic peptide is shown for example after a marathon.
Different studies, conducted with cardiac magnetic resonance imaging, identified the presence of fibrosis, ischemic or mainly non-ischemic. However, other studies did not show any kind of transitory or permanent cardiac lesion after strenuous exercise. Moreover, could we consider some responses, such as an increase in cardiac biomarkers, a protective rather than a damage response?
In this context, experimental and human studies on cardiac response to continuous ischemic stimuli introduced new physiopathological concepts and terms, such as cardioprotection or preconditioning. Could we use these terms, and thus, the corresponding molecular, biochemical, hormonal and functional mechanisms in physiological terms, that is a normal response of a healthy heart to an environmental or situational condition of strenuous exercise?
This Research Topic is focused on the cardiovascular acute response and chronic adaptation to strenuous conditions according to a translational approach. In particular, it is intriguing to have results of the relationship between the heart and other organs, such as the brain, and systems, such as hormones, inflammatory and immune ones, in a systemic and holistic perspective of human physiology. Finally and provocatively, we aim to translate some terms commonly used in the cardiovascular disease context, such as cardioprotection or preconditioning, to a physiological scenario, like strenuous exercise or strenuous environment, of a healthy heart.