مطالب

Purpose: Winter endurance training combines high aerobic load with repeated cold exposure, which can alter immune-related cellular signaling and increase vulnerability to upper respiratory tract infections (URTI), thereby threatening training continuity and performance. This structured abstract aimed to summarize a signaling-based rationale for immune-informed winter periodization in endurance runners. Method: A narrative, mechanistic synthesis was developed from exercise immunology and cold-stress evidence, focusing on how cold exposure and endurance exercise converge on sympathetic nervous system and hypothalamic–pituitary–adrenal (HPA) axis activation, downstream endocrine responses (catecholamines, cortisol), immune cell trafficking, airway barrier function, mucosal immunity (salivary IgA), and cytokine signaling (with emphasis on IL-6). Practical implications were translated into microcycle/mesocycle design principles and a tiered monitoring framework. Results: Cold exposure triggers thermoregulatory vasoconstriction and central blood redistribution and is accompanied by neuroendocrine shifts that can modify leukocyte behavior, adhesion signaling, and lymphocyte proliferation. Evidence indicates that respiratory barrier defenses may be impaired in cold conditions, while mucosal immunity (e.g., IgA-related protection) can be reduced in heavily trained athletes during winter, coinciding with increased URTI reports. IL-6 responses to exercise in the cold were context-dependent: some protocols show minimal temperature effects at moderate intensity, whereas others report higher IL-6 at colder temperatures, supporting a multi-marker and longitudinal interpretation rather than reliance on single measurements. Conclusion: Integrating cellular signaling knowledge enables temperature-aware planning of intensity, structured warm-up/rewarming routines, monotony control, and symptom-gated adjustments to reduce “vulnerability windows” without sacrificing adaptation. Immune-informed winter periodization, supported by feasible monitoring (load, sleep, symptoms, and optional IgA/cytokines), may preserve training availability and mitigate winter performance decrement in endurance runners.

Purpose: Extreme sport tourism has become a rapidly expanding segment of the global tourism industry, involving high-risk activities such as rafting, climbing, sky running, and canyoning. The objective of this review was to synthesize current scientific evidence on the physiological and organizational determinants of safety in extreme sport tourism and to present an integrated framework applicable to diverse adventure sport contexts. Method: A narrative review methodology was adopted. Peer-reviewed studies published between 2000 and 2025 were identified through PubMed, Scopus, Web of Science, ScienceDirect, and Google Scholar. Included studies addressed physiological stress responses, environmental exposure, guide competence, safety management systems, and emergency preparedness in extreme or adventure sport settings. Findings were thematically synthesized across physiological and organizational domains. Results: The review identified key physiological determinants of safety, including cardiovascular strain, hypoxic and respiratory stress, thermoregulatory imbalance, dehydration, neuromuscular fatigue, and neuroendocrine stress responses, all of which influence performance, cognition, and decision-making under extreme conditions. Organizational determinants included structured risk assessment, guide training and certification, equipment standards, communication systems, emergency response planning, and organizational safety culture. Evidence indicated that inadequate organizational control amplifies physiological risk and contributes to accident occurrence. Conclusion: Safety in extreme sport tourism requires an integrated, multidisciplinary approach aligning human physiological limits with organizational management to improve participant safety and support sustainable destination development.