Physiological and psychological determinants of cardiovascular autonomic response in experienced Cold-Water Swimmers

Introduction: The relationship between morphological and psychological parameters and cardiovascular autonomic responses was investigated in experienced cold-water swimmers. Objective: This study explores how morphological and psychological factors influence cardiovascular autonomic responses in experienced cold-water swimmers. Methodology: Conducted as a cross-sectional observational study, the research involved 18 training swimmers who regularly engage in icy-water swimming (below 5°C). Participants were assessed at four key time points: baseline, pre-dive, post-dive, and recovery. Cardiovascular parameters, heart rate variability (HRV), and psychological states were measured using validated tools. Results: Cold-water immersion triggered significant reductions in HRV, particularly in RMSSD and SDNN (p < 0.01), indicating elevated sympathetic activity and decreased parasympathetic modulation. Notably, overall autonomic function, reflected by a decline in the PNS index (β = -0.73, p < 0.01), was inversely associated with anxiety (β = -0.64, p < 0.01) and depression levels (β = -0.49, p < 0.05). These findings underscore the essential role of mental health in shaping physiological resilience in extreme environments. Body composition, especially visceral fat, was also found to significantly influence autonomic regulation (β = -0.77, p < 0.01). Conclusions: This study emphasizes the importance of integrated training strategies that address both physiological conditioning and psychological support to enhance performance and ensure safety in cold-water environments. The results provide deeper insight into the multifaceted challenges cold-water swimmers face and highlight the need for tailored interventions to support their unique physiological demands.