Effects of Exercising With a Facemask on Cardiorespiratory Performance at Intensities Below and Above the Ventilatory Threshold

Tests will be carried out during the afternoon period (between 13.00 and 16.00 h), in a laboratory with an environmental temperature between 22 and 24 ºC and a relative humidity between 44 and 56%.

Each participant will be tested on 3 non-consecutive days. On the first day, a Graded Exercise Testin (GXT) will be performed, to measure VO2max and to enable the individualization of intensities according to the VT of each participant. (Silva et al., 2011). Then, in a randomized (computer generated algorithm) counterbalanced manner, all participants performed resting and standardized cycle-ergometer submaximal protocols on two different conditions (with and without facemask), within a 1-week period. On the first visit, body mass measurements will be taken, to the nearest 0.01 kg, on a digital scale (BG 42, Breuer GmbH, Söflinger, Germany) with the participants wearing light-weight clothes and no shoes. Measurements of standing height will be limited to the first visit and taken to the nearest 0.5 cm using a stadiometer. Body Mass index (BMI) will be calculated by dividing the participants' mass in kilograms by the square of their height in meters. Then, after a brief warm-up period, each participant will perform a maximal cycle-ergometer test consisting of a ramp protocol to volitional exhaustion.

One of our purposes is to determine the impact of exercising with a facemask on physiological recovery. For this reason, measurements, within each submaximal testing session (with and without a facemask), will be taken using a standardized timeline designed to allow measuring recovery postsubmaximal exercise and compare it with a resting baseline time point. Specifically, testing will begin with a 10-min resting period in the seated position (baseline). Subsequently, participants will exercise either without (control) or with (experimental) a surgical facemask at an intensity below the VT and recover for another 10 min. Then, each participant will exercise at an intensity above the VT until volitional exhaustion and this will be followed by 10 min of recovery.