STRESS AND FREQUENCY VARIABILITY CARDIAC IN EXTREME ENVIRONMENTS: A SYSTEMATIC REVIEW

The aim of this study was to investigate, through the literature, the possible physiological alterations in cardiac autonomic control - assessed through heart rate variability (HRV) - and stress markers - such as cortisol - resulting from exposure to extreme environments - isolated, confined, and extreme (ICE). A qualitative research approach, specifically an systematic Literature Review, was conducted using the PICO strategy, targeting studies from the last 05 years freely available and relevant to the topic. Searches were performed in the Virtual Health Library (VHL), via MEDLINE and PubMed, using the following DeCS/MeSH descriptors combined with the boolean operator "AND": "Confined environment and Antarctica," "Extreme environment and Antarctica," "Isolated and Antarctic environment," "heart rate variability and Antarctica," "stress and Antarctica," "stress and isolated environment," "heart rate variability and isolated environment." In total, 328 studies were initially identified, and after eligibility screening, 4 studies remained for qualitative synthesis. The neurophysiological effects of ICE environments are evident, with results indicating a reduction in parasympathetic activation during sleep, impacting sleep quality. Additionally, it may lead to decreased daytime cortisol levels associated with fatigue and hinder the ability to cope with stress. Future research is crucial to further understand these effects, necessitating new approaches to investigate the impacts on human health and the quality of life of individuals exposed to such environments.