Design comprised seven 10-minute testing conditions split in two parts. Five were at rest and sitting on a chair: i. Baseline without gas mask; ii. Baseline with gas mask; iii. Hypoxemia without mask; iv. Hypoxemia with gas mask; and v. Hypoxemia corrected. Two effort conditions were programmed at 7 METS Effort Zone and were performed on Treadmill (Constant 3 MPH speed and 10% inclination). These were with and without the gas mask. Between the rest-condition a 5-minute wash-out took place while for the effort a ten-minute was applied.