TABLE 4.

The comparison of pulmonary ventilation parameters between mask-on and mask-off condition.

	Mask-off	Mask-on	Cohen’s d effect size	P value
$\stackrel{.}{\text{V}}$E (l/min)
Rest	10.7 ± 3.07	8.84 ± 2.94	0.62	<0.001
Warm up	15.8 ± 2.70	13.1 ± 3.64	0.82	<0.001
AT	29.5 ± 6.56	25.8 ± 8.13	0.50	<0.001
Peak	66.5 ± 17.9	55.1 ± 17.3	0.65	<0.001
VT (l)
Rest	0.59 ± 0.20	0.57 ± 0.27	0.08	0.083
Warm up	0.79 ± 0.28	0.74 ± 0.37	0.15	0.017
AT	1.28 ± 0.41	1.27 ± 0.49	0.02	0.388
Peak	1.79 ± 0.50	1.66 ± 0.45	0.27	<0.001
BR (%)
Rest	91.3 ± 2.26	92.8 ± 2.37	0.64	<0.001
Warm up	87.3 ± 2.64	89.4 ± 2.87	0.76	<0.001
AT	76.7 ± 5.02	79.7 ± 5.43	0.58	<0.001
Peak	48.4 ± 10.9	57.0 ± 11.3	0.77	<0.001
Rf (b/min)
Rest	19.1 ± 4.51	16.5 ± 4.59	0.56	<0.001
Warm up	21.4 ± 5.18	19.3 ± 5.52	0.38	0.001
AT	24.3 ± 5.65	21.7 ± 6.38	0.43	<0.001
Peak	37.9 ± 6.72	33.8 ± 7.98	0.55	<0.001
SpO2 %
Rest	94.9 ± 20.6	97.9 ± 12.1	0.17	0.161
Warm up	95.8 ± 17.0	97.5 ± 12.2	0.11	0.144
AT	96.9 ± 12.3	96.8 ± 8.51	0.01	0.094
Peak	95.3 ± 8.72	95.3 ± 9.25	0.001	0.564
PetO2 (mmHg)
Rest	108.9 ± 10.9	108.9 ± 6.09	0.005	0.266
Warm up	107.6 ± 9.68	105.1 ± 11.0	0.24	<0.001
AT	105.1 ± 8.59	103.2 ± 9.38	0.21	0.002
Peak	115.7 ± 9.75	112.2 ± 11.0	0.33	<0.001
PetCO2 (mmHg)
Rest	34.2 ± 10.3	34.9 ± 8.03	0.08	0.040
Warm up	36.5 ± 8.85	37.4 ± 9.64	0.10	0.027
AT	42.2 ± 7.86	43.6 ± 8.40	0.17	0.001
Peak	38.8 ± 9.70	41.6 ± 10.2	0.28	<0.001
$\stackrel{.}{\text{V}}$E/$\stackrel{.}{\text{V}}$O2
Rest	33.2 ± 5.49	32.6 ± 6.16	0.11	0.350
Warm up	30.3 ± 3.67	28.2 ± 4.93	0.47	<0.001
AT	27.4 ± 3.38	26.2 ± 4.04	0.33	0.001
Peak	39.6 ± 5.80	36.4 ± 6.82	0.51	<0.001
$\stackrel{.}{\text{V}}$E/$\stackrel{.}{\text{V}}$CO2
Rest	38.8 ± 6.17	37.4 ± 7.24	0.21	0.049
Warm up	34.5 ± 4.46	32.6 ± 5.86	0.36	<0.001
AT	27.9 ± 3.34	26.9 ± 4.04	0.27	0.002
Peak	30.3 ± 3.87	28.8 ± 4.68	0.34	<0.001
$\stackrel{.}{\text{V}}$E/$\stackrel{.}{\text{V}}$CO2 slope	26.4 ± 3.38	26.0 ± 4.49	0.08	0.512

The values were shown in mean ± standard deviation. Significance level was set at P < 0.05. $\stackrel{.}{\text{V}}$_E, minute ventilation; V_T, tidal volume; BR, breathing reserve; Rf, breathing frequency; SpO₂, percutaneous oxygen saturation; PetO₂, end-tidal oxygen partial pressure; PetCO₂, end-tidal carbon dioxide partial pressure; $\stackrel{.}{\text{V}}$CO₂, carbon dioxide production; $\stackrel{.}{\text{V}}$CO₂, carbon dioxide output; AT, anaerobic threshold. Significant results are indicated in bold.