Journal Article

Combined effects of normobaric hypoxia and cold on respiratory system responses to high‐intensity exercise

Savoldelli, Aldo, Pellegrini, Barbara, Decet, Marco, Fornasiero, Alessandro, Bortolan, Lorenzo, Dorelli, Gianluigi, Schena, Federico, Callovini, Alexa

2025

Overview

Cold temperatures (<−15°C) increase exercise‐induced bronchoconstriction (EIB), while hypoxic‐induced hyperventilation exacerbates respiratory muscle fatigue for a given exercising task. This study aimed to determine the individual and combined effects of cold and normobaric hypoxia on the respiratory system responses to high‐intensity exercise. Fourteen trained male runners (V̇O2max${{\\dot{V}}_{{{\\mathrm{O}}}_2}{\\mathrm{max}}}$: 64 ± 5 mL/kg/min) randomly performed an incremental cardiopulmonary exercise test (CPET) to volitional exhaustion under four environmental conditions: normothermic (18°C) normoxia (FIO2${{F}_{{\\mathrm{I}}{{{\\mathrm{O}}}_2}}}$: 20.9%) and hypoxia (FIO2${{F}_{{\\mathrm{I}}{{{\\mathrm{O}}}_2}}}$: 13.5%), and cold (−20°C) normoxia and hypoxia. Ventilatory responses during exercise and lung function (LF), maximal inspiratory (MIP) and expiratory (MEP) pressure measurements before and after exercise were evaluated. Volume of air forcefully exhaled in 1 s (FEV1), FEV1/forced vital capacity (FVC), peak expiratory flow, forced expiratory flow during the mid (25–75%) portion of the FVC, and maximal expiratory flow at 50% of FVC were affected by cold exposure. No significant pre‐ to post‐exercise change in MIP and MEP was found, independent of environmental conditions. Greater LF impairments in cold‐normoxia and coldhypoxia were associated with the lowest peak ventilatory responses during exercise. Cold exposure was found to negatively impact peak ventilatory responses and post‐exercise LF, further highlighting a relationship between EIB presence and the blunted ventilatory response in the cold. Respiratory muscle strength remained unchanged after exercise regardless of the environmental condition, suggesting no detrimental effect of hypoxia on this parameter when intermittent short‐duration high‐intensity exercises are performed. Future studies should investigate the combined cold‐hypoxic effect on longer exercise durations at a sustained high intensity, accounting for differences between normobaric and hypobaric hypoxia exposures. What is the central question of this study? What are the independent and combined effects of cold and normobaric hypoxia on respiratory responses to high‐intensity exercise? What is the main finding and its importance? Cold exposure impaired lung function and peak ventilatory responses during high‐intensity exercise, with greater impairments observed under combined cold‐hypoxia condition. The findings highlight a link between exercise‐induced bronchoconstriction and reduced ventilatory capacity in cold environments. Respiratory muscle strength remained unaffected post‐exercise across all conditions, suggesting no detrimental impact of hypoxia during short‐duration high‐intensity tasks.

• Publisher: John Wiley & Sons, Inc,Wiley
• Subject: Adult / Bronchoconstriction / Bronchoconstriction - physiology / Cold / cold exposure / Cold Temperature / Environmental conditions / Exercise - physiology / Exercise Test - methods / exercise‐induced bronchoconstriction / high‐intensity exercise / Humans / Hyperventilation / Hyperventilation - physiopathology / Hypoxia / Hypoxia - physiopathology / Male / Muscle Fatigue - physiology / Muscle strength / normobaric hypoxia / Oxygen Consumption - physiology / Respiratory function / Respiratory Muscles - physiology / Respiratory Muscles - physiopathology / respiratory responses / Respiratory system / Respiratory System - physiopathology / Running - physiology / Ventilatory behavior / Young Adult