Document Type : Letter to Editor
Author
Department of Exercise Physiology, Faculty of Physical Education and Sports Sciences, Allameh Tabataba’i University, Tehran, Iran.
Abstract
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.
Keywords
Main Subjects
)