Physiological Adaptation and Transition to Pathology: Lessons from Exercise Physiology and Ergonomics in Extreme Environments

Extreme environmental conditions such as cold exposure, hypoxia, and physical load challenge human physiological homeostasis and may trigger a transition from adaptive responses to pathological processes. Understanding these mechanisms is essential not only for environmental and occupational physiology but also for clinical medicine, where similar physiological constraints occur during surgery, critical illness, and rehabilitation. This review integrates findings from three complementary research projects conducted at the Jožef Stefan Institute investigating field-based ergonomics, peripheral vascular responses to cold and hypoxia, and metabolic adaptations during prolonged normobaric hypoxic exposure. The studies demonstrate that environmental stressors interact through systemic physiological mechanisms affecting thermoregulation, microcirculation, energy metabolism, and functional performance. Cold-induced vasodilation (CIVD) emerges as a dynamic marker of physiological adaptability, while hypoxia influences both peripheral vascular regulation and whole-body metabolic balance. Together, these findings provide translational insights into vascular dysfunction, tissue perfusion, metabolic resilience, and perioperative physiology, highlighting the continuum between environmental adaptation and clinically relevant pathology.