A heat and moisture-exchanging mask impairs self-paced maximal running performance in a sub-zero environment

Abstract

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.<p>

<p>Methods - Twenty-three healthy adults (15 male, 8 female; age 18–53 years; V˙O_2peak 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 (<i>f</i>_R), and thoracic area skin temperature (<i>T</i>_sk) 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.<p>

<p>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 (<i>r</i>² = 0.22). SmO2 and [HHb] were 3.1% lower and 0.35 arb. unit higher, respectively, during the TT with HME, and <i>T</i>_sk was 0.66 °C higher during the HME TT in men. HR (+ 2.7 beats·min⁻¹) and <i>T</i>_sk (+ 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.