Peak oxygen consumption and lactate threshold in full mask versus mouth mask conditions during incremental exercise

Abstract

Respirator masks vary in inhalation and exhalation resistance, and in dead volume. It is believed that these factors may contribute significantly to an early anaerobic threshold in mask wearers during maximal exercise. Very little is known concerning the effect of respirator masks on maximal oxygen consumption$(\dot VO_{2max} )$ and the lactate threshold (LT). The purpose of the present study was to assess peak$\dot VO_2$ $(\dot VO_{2peak} )$ LT and the ventilatory threshold (VT) of 14 experienced cyclists performing two maximal cycle exercise protocols while wearing a full respirator mask (FM) (M17 type) and a mouth mask (MM).$\dot VO_{2peak}$ was 10% lower under FM conditions. Peak values for ventilation$(\dot V_{Epeak} )$, respiratory rate (f _bpeak) and tidal volume (V _Tpeak) were all significantly lower under with FM versus MM conditions. Performance time and maximal heart rate (f _cpeak) were not different between mask conditions. The LT and VT when expressed in %$\dot VO_{2peak}$ and the lactate concentration (mmol · l⁻¹ at LT and VT were not significantly different across mask conditions. Bland-Altman plots demonstrated longer inhalation times, decreasedf _r values and greater oxygen extraction under FM conditions. Thus, perhaps due to the increased inhalation resistance of the FM condition, subjects were unable to attain their “normal”$\dot VO_2$ despite similar performance times and maximalf _c. Furthermore, despite a diminished$\dot VO_{2peak}$ with FM, LT and VT appeared to be the same as with a MM.