Purpose Heat-and-moisture-exchanging devices (HME) are commonly used by endurance athletes during training in sub-zero environments, but their effects on performance are unknown. We investigated the influence of HME usage on running performance at − 15 °C. Methods Twenty-three healthy adults (15 male, 8 female; age 18–53 years; $$\dot{V}{\text O}_{2peak}$$ V ˙ O 2 p e a k men 56 ± 7, women 50 ± 4 mL·kg−1·min−1) performed two treadmill exercise tests with and without a mask-style HME in a randomised, crossover design. Participants performed a 30-min submaximal warm-up (SUB), followed by a 4-min maximal, self-paced running time-trial (TT). Heart rate (HR), respiratory frequency (fR), and thoracic area skin temperature (Tsk) were monitored using a chest-strap device; muscle oxygenation (SmO2) and deoxyhaemoglobin concentration ([HHb]) were derived from near-infra-red-spectroscopy sensors on m. vastus lateralis; blood lactate was measured 2 min before and after the TT. Results HME usage reduced distance covered in the TT by 1.4%, despite similar perceived exertion, HR, fR, and lactate accumulation. The magnitude of the negative effect of the HME on performance was positively associated with body mass (r2 = 0.22). SmO2 and [HHb] were 3.1% lower and 0.35 arb. unit higher, respectively, during the TT with HME, and Tsk was 0.66 °C higher during the HME TT in men. HR (+ 2.7 beats·min−1) and Tsk (+ 0.34 °C) were higher during SUB with HME. In the male participants, SmO2 was 3.8% lower and [HHb] 0.42 arb. unit higher during SUB with HME. Conclusion Our findings suggest that HME usage impairs maximal running performance and increases the physiological demands of submaximal exercise.

Purpose Cold air exposure is associated with increased respiratory morbidity and mortality. Repeated inhalation of cold and dry air is considered the cause of the high prevalence of asthma among winter endurance athletes. This study assessed whether a heat- and moisture-exchanging breathing device (HME) attenuates airway responses to high-intensity exercise in sub-zero temperatures among healthy subjects. Methods Using a randomized cross-over design, 23 healthy trained participants performed a 30-min warm-up followed by a 4-min maximal, self-paced running time trial in − 15 °C, with and without HME. Lung function was assessed pre- and immediately post-trials. Club cell protein (CC-16), 8-isoprostane, and cytokine concentrations were measured in plasma and urine pre- and 60 min post trials. Symptoms were assessed prior to, during, and immediately after each trial in the chamber. Results HME use attenuated the decrease in forced expiratory volume in 1 s (FEV1) post trials (∆FEV1: mean (SD) HME − 0.5 (1.9) % vs. no-HME − 2.7 (2.7) %, p = 0.002). HME also substantially attenuated the median relative increase in plasma-CC16 concentrations (with HME + 27% (interquartile range 9–38) vs no-HME + 121% (55–162), p < 0.001) and reduced airway and general symptom intensity, compared to the trial without HME. No significant changes between trials were detected in urine CC16, 8-isoprostane, or cytokine concentrations. Conclusion The HME attenuated acute airway responses induced by moderate-to-maximal-intensity exercise in − 15 °C in healthy subjects. Further studies are needed to examine whether this HMEs could constitute primary prevention against asthma in winter endurance athletes.

Heat-and-moisture exchanging devices (HME) are commonly used by winter endurance athletes during training in sub-zero environments, but their effect on performance is unknown. This study aimed to investigate the effect of an HME on running performance at -15°C in healthy people. Twenty-three healthy adults (15 male, 8 female; age 18-53 y; VO2peak men 56 ± 7, women 50 ± 4 mL·kg-1·min-1) performed two treadmill exercise tests with and without HME in a randomized, crossover design. Participants performed a 30-min submaximal warm-up (SUB), followed by a 4-min maximal, self-paced running time-trial (TT). Heart rate (HR) and respiratory frequency (fR) were monitored using a chest strap; muscle oxygenation (SmO2) and deoxyhemoglobin concentration ([HHb]) were derived from wireless near-infrared-spectroscopy sensors on m. vastus lateralis; blood lactate was measured 2-min before and after the maximal test. HME reduced distance covered in the TT by 1.4% (p = 0.033), despite similar perceived exertion, HR, fR and lactate accumulation. The magnitude of the effect of the HME on performance was associated with body mass (r2 = 0.22, p = 0.027), but not aerobic fitness or maximal ventilation. SmO2 and [HHb] were lower (-3.1%, p &lt; 0.001) and higher (0.35 AU, p &lt; 0.001), respectively, during the TT with HME. HR was 2.7 beats·min-1 higher during SUB with HME (p &lt; 0.001). In the male participants, SmO2 was lower (-3.8%, p &lt; 0.001) and [HHb] higher (0.42 AU, p &lt; 0.001) during SUB with HME. Our findings suggest that HME usage impairs maximal running performance and increases the physiological demands of submaximal exercise.

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