Impact of cold air exposure on respiratory physiology during light-to-moderate physical activity in healthy adults

Working in cold environments presents unique physiological challenges, and this study sought to investigate the specific impacts of cold air exposure on ventilation during light-to-moderate physical activity simulating occupational work demands. Fourteen healthy adults (3 females; age: 24 ± 6 years) completed five 20-min treadmill walking bouts across three environmental conditions (20°C, 10°C, and 0°C) in a randomized, crossover design. Respiratory variables, including minute ventilation (VE), breathing frequency (RR), and tidal volume (Vt), were measured, as well as heart rate (HR) and ratings of perceived exertion (RPE). Data were analyzed using repeated-measures ANOVA. VE was significantly higher at 0°C compared to both 10°C (mean difference [Δ]: +2.08 L·min^-1, p < 0.001) and 20°C (Δ: +1.62 L·min^-1, p < 0.001) during the final exercise stage. This increased ventilation was primarily driven by a significant increase in Vt at 0°C compared to 10°C (Δ: +0.11 L, p = 0.002) and 20°C (Δ: +0.13 L, p = 0.002). RR and RPE did not differ between conditions, while HR was modestly affected by temperature. Cold air exposure significantly alters ventilatory patterns during light-to-moderate physical activity. Increased ventilation observed at colder temperatures is primarily mediated by increases in Vt. These findings provide insight into acute cold-air respiration and highlight implications for performance in austere environments.