Table 3.

Physiologic variables at minute 6 and after 6-minute walk tests in each condition

End	No mask	Surgical mask	N95 mask	Cloth mask	P
HR, bpm	137 ± 20	133 ± 20	134 ± 16	133 ± 21	0.84
Systolic, mmHg	125 ± 14	124 ± 14	125 ± 14	125 ± 14	0.96
Diastolic, mmHg	77 ± 7	77 ± 8	77 ± 8	77 ± 9	0.99
SPO2, %	97 (96–97)	96 (95–97)	96 (95–97)	97 (96–97)	0.051
Dyspnea, Borg unit	2 (0.5–4)	2 (2–4)	2 (1–4.5)	3 (2–5)	0.02*
Effort of breathing, Borg unit	2 (0.5–4)	2 (1.5–4)	3 (2–5.5)	4 (2.5–6)	< 0.001*
Leg fatigue, Borg unit	2 (1–5.5)	3 (1.5–5)	3 (1.5–4)	2 (1–5)	0.47
HRR at 1 min, bpm	105 ± 17	109 ± 13	108 ± 17	105 ± 13	0.22
6MWD, meters	599 ± 66	593 ± 55	593 ± 56	589 ± 56	0.59
Estimated VO2 max, ml/kg/min	42.7 ± 4.2	41.7 ± 4.1	42.9 ± 4.5	42.6 ± 4.2	0.11

Note: Values are means ± SD or median (upper-lower quartile). HR = heart rate; bpm = beats per minute; HRR = heart rate reserve; SPO₂ = oxygen saturation; VO₂ max = maximal oxygen consumption; 6MWD = 6 minutes walking distance.

^*P < 0.05 statistically significant differences between four groups by one-way repeated ANOVA or Friedman test.