Table 3.

Results of generalized linear mixed (GLM) model analysis of the sum of Comfort Score (a) and Symptom Score (b) in 40 subjects without mask (NM) and with masks (SM, CM, FFP2) during physical exertion (ergometry, CPET) and during 4 h workplace examination.

	Reference	Δ mask vs. no mask
	Sum score without mask (NM)	SM	CM	FFP2
(a) Comfort Score
Ergometry
Pre	9.09	0.96	1.46	3.05
E1	9.10	2.49	2.48	5.29
		0.007	0.077	0.001
E2	9.77	4.39	5.15	8.93
		< 0.0001	< 0.0001	< 0.0001
E3	10.77	6.57	6.94	13.70
		< 0.0001	< 0.0001	< 0.0001
Post	10.75	4.95	5.55	11.06
		< 0.0001	< 0.0001	< 0.0001
CPET
Pre	12.89	0.53	1.03	1.62
E1	13.99	1.10	1.58	3.55
		0.576	0.636	0.097
E2	16.91	1.19	2.43	5.00
		0.677	0.389	0.036
E3	20.20	2.27	3.93	6.68
		0.291	0.108	0.009
Post	18.06	1.42	2.07	3.91
		0.569	0.610	0.218
Workplace
Pre	9.30	0.65	0.13	0.23
30	9.04	2.49	2.53	6.53
		0.002	< 0.0001	< 0.0001
60	9.05	3.33	3.44	7.15
		< 0.0001	< 0.0001	< 0.0001
90	9.03	3.52	3.96	9.15
		< 0.0001	< 0.0001	< 0.0001
150	9.06	3.77	4.01	10.55
		< 0.0001	< 0.0001	< 0.0001
210	9.16	3.92	6.94	11.03
		< 0.0001	< 0.0001	< 0.0001
240	9.03	4.40	4.18	11.91
		< 0.0001	< 0.0001	< 0.0001
Post	9.05	0.56	0.82	0.45
		0.877	0.125	0.612
(b) Symptom Score
Ergometry
Pre	16.24	0.11	0.15	0.05
Post	17.62	1.17	1.00	2.41
		0.023	0.064	< 0.0001
CPET
Pre	16.52	0.12	0.49	0.7
Post	18.74	1.07	0.72	2.08
		0.138	0.796	0.054
Workplace
Pre	16.27	0.27	0.19	0.07
30	6.18	0.62	0.45	1.38
		0.286	0.410	< 0.0001
60	16.20	0.97	0.77	1.92
		0.083	0.144	< 0.0001
90	16.22	1.13	0.84	2.17
		0.031	0.097	< 0.0001
150	16.17	1.19	0.87	2.76
		0.044	0.133	< 0.0001
210	16.40	1.30	0.81	3.17
		0.043	0.211	< 0.0001
240	16.37	1.26	0.89	2.99
		0.057	0.174	< 0.0001
Post	16.18	0.47	0.34	0.73
		0.508	0.613	0.026

The situation without mask at each time of measurement was always used as reference. For NM geometric mean, for the three mask types (SM, CM, FFP2) differences to NM (Δ) and p values (< 0.05 marked bold) are shown.

The load levels correspond to light work (pre and post), moderate (E1), heavy (E2) and very heavy work (E3).

NM no mask, SM surgical mask, CM community mask, FFP2 filtering face piece class 2, CPET cardiopulmonary exercise test.