Table 4.

Physiologic and subjective parameters over 1 hour of treadmill exercise at ambient conditions of 35°C and relative humidity 50%

Parameters	Control	N95 FFR	P100 FFR
O2 saturation (%)
0 min	98.1 ± 0.7	98.2 ± 0.8	97.8 ± 0.9
20 min	97.8 ± 0.6	97.8 ± 1.0	97.3 ± 1.0
40 min	97.6 ± 1.0	97.5 ± 0.7	97.7 ± 1.2
60 min	97.9 ± 1.1	97.8 ± 0.6	97.3 ± 0.8
Transcutaneous CO2 (mm Hg)
0 min	40.8 ± 1.8	39.3 ± 4.0	41.2 ± 1.3
20 min	41.6 ± 2.5	41.8 ± 2.7	42.8 ± 2.7
40 min	41.6 ± 3.1	41.7 ± 2.4	42.7 ± 2.0
60 min	40.9 ± 2.4	41.3 ± 2.4	42.6 ± 2.1
Heart rate (beats/min)
0 min	74.0 ± 7.8	72.8 ± 16.1	68.1 ± 13.2
20 min	100.4 ± 12.4	97.7 ± 10.3	98.7 ± 10.7
40 min	104.3 ± 14.9	101.1 ± 12.2	101.1 ± 9.8
60 min	106.2 ± 14.8	105.9 ± 11.9	105.1 ± 9.2
Respiratory rate (breaths/min)
0 min	15.1 ± 6.4	15.4 ± 4.7	16.0 ± 2.6
20 min	27.1 ± 5.1	27.1 ± 2.8	26.8 ± 8.0
40 min	27.3 ± 6.5	28.8 ± 3.4	28.6 ± 6.8
60 min	28.1 ± 7.1	28.4 ± 3.2	29.3 ± 6.5
Breathing comfort (1 [no discomfort] to 7 [intolerable discomfort])
0 min	1.0 ± 0.0	1.1 ± 0.3	1.1 ± 0.3
20 min	1.3 ± 0.5	1.8 ± 0.6∗	1.6 ± 0.5∗
40 min	1.6 ± 0.8	2.1 ± 0.5∗	2.0 ± 0.7∗
60 min	1.7 ± 0.8	2.2 ± 0.6∗	2.4 ± 0.5∗
Thermal sensation (0 [coldest] to 5 [neutral] to 10 [hottest])
0 min	4.8 ± 0.4	4.8 ± 0.6	4.8 ± 0.4
20 min	5.8 ± 0.5	5.8 ± 0.5	5.9 ± 0.3
40 min	6.3 ± 0.5	6.3 ± 0.6	6.3 ± 0.5
60 min	6.4 ± 0.5	6.6 ± 0.5	6.7 ± 0.5
Exertion (Borg scale 6-20 [no exertion at all] to 11 [light exertion] to 20 [maximal exertion])
0 min	6.0 ± 0.0	6.2 ± 0.4	6.0 ± 0.0
20 min	8.1 ± 1.4	8.2 ± 1.6	8.0 ± 1.2
40 min	9.1 ± 2.0	9.5 ± 1.9	9.6 ± 1.6
60 min	9.3 ± 2.0	9.9 ± 2.1	10.5 ± 1.7

NOTE. Values are mean ± SD.

Abbreviation: FFR, filtering facepiece respirator.

^∗Significantly different from controls (P < .05).