The Impact of Commonly-Worn Face Masks on Physiological Parameters and on Discomfort During Standard Work-Related Physical Effort
; ; ; ;
In view of the pandemic spread of SARS-CoV-2, there is increasing evidence that face masks should be worn in public spaces as an integral part of hygiene measures to contain the virus (1). Currently, the most common face masks are FFP2 masks (suitable for self-protection), surgical masks, and cloth masks (“community masks”) that are often used in the non-clinical setting. With their increasing use among the general population, more reports have suggested that mask wearing presents a health risk (2–4). In contrast to their effectiveness in infection prophylaxis, the effects of the above mask types on physiological parameters (blood gases, vital parameters) and the subjective perception of exertion under workload conditions have not yet been systematically investigated.
Voluntary study participants (N = 26) from the hospital staff first had one minute without exercise (baseline) and then performed tests of exertion at work-typical levels (50/75/100 watts, for three minutes each, in direct succession), wearing the different face masks (cloth, surgical, or FFP2) or no mask, to measure changes in blood gases (transcutaneous carbon dioxide partial pressure [PtcCO2], pulse oximeter–derived oxygen saturation [SpO2]), and vital parameters (heart rate, respiratory rate, and arterial blood pressure; recorded non-invasively). The order of mask wearing was different and randomized from person to person. A five- to ten-minute rest period was given at each mask change.
The measured parameters were compared with the subjective perceived exertion (Borg’s scale [with 6 points corresponding to “very, very light”, and 20 points corresponding to “very, very difficult”]) and clinical characteristics (age, body mass index [BMI], sex, nicotine use, and hypertension). In order to detect potential pulmonary limitations, spirometry was performed at rest before the experiment was carried out. In addition, mask-related main symptoms during exercise were recorded. Mask-specific group differences were determined using one-way analysis of variance. The Pearson correlation coefficient was used for parametric distribution. This study received ethics approval from the ethics committee of the Medical School Brandenburg (E-01–20200527).
Overall, 24 of the participants finished all conditions and were included with complete data. Independent of the mask type, two participants had to stop the assessment prematurely due to muscular exhaustion or joint problems. Based on the participant characteristics (age 44.7 ± 11.7 years; 46% male; BMI 25.4 ± 4.3; 26.9% smoker; 19.2% with arterial hypertension; FEV1 / FVC 101.6 ± 7.4%) as well as diversity in areas of work and fitness levels, a good cross-section of the hospital workforce can be assumed.
During exercise, the PtcCO2 (which corresponds to arterial CO2 partial pressure) increased more distinctly for all three mask types as compared to exercise without a mask (100 watts: factor 2.7 with a FFP2 mask; factor 2.2 with a surgical mask; factor 1.8 with a cloth mask; p <0.001 each). At 100 watts, the SpO2 levels fell more sharply while wearing the FFP2 mask than during exercise with no mask (−1.54% versus −0.71%; p = 0.005) (Table). No mask-specific changes were observed for vital parameters. The subjective perception of exertion was on average highest while wearing the FFP2 mask (14.6 points on the Borg scale), and lowest while wearing no mask (11.9 points). A high perception of exertion correlated across all mask types (FFP2 / surgical / cloth) with a higher heart rate (r = 0.737 / 0.752 / 0.641; p = <0.001 / <0.001 / 0.002, respectively) and respiratory rate (r = 0.463 / 0.510 / 0.503; p = 0.023 / 0.011 / 0.012, respectively), but it did not correlate with levels of increased CO2 (r = –0.026 / –0.260 / –0.380; p = 0.903 / 0.220 / 0.080, respectively). No relevant correlations were observed for clinical characteristics or resting spirometry measures.
During bicycle ergometry, 14 out of 24 participants reported mask-specific discomfort (dyspnoea, n = 11; headache, n = 4; feeling hot, n = 2; dizziness, n = 1); 13 of these 18 discomfort reports (72%) were related to FFP2 masks.
During exertion, wearing a commonly-used face mask led to measurable but clinically irrelevant changes in blood gases as compared to not wearing a mask. The mask-specific absolute differences for PtcCO2 / SpO2 were small (maximum 4.3 mmHg / −1.54% while wearing a FFP2 mask). In addition, the described symptoms when wearing each type of mask did not correlate with the levels of the exercise-related increases in CO2 or drop in SpO2, but did correlate with increases in respiratory and heart rates. A critical threshold for clinically significant hypercapnia/hypoxemia is not defined in the current guidelines as it differs greatly between individuals and depends on the respective baseline value. In general, perceived changes in healthy individuals are only to be expected from PaCO2 values >60 mmHg (5), although even minor increases in PaCO2 due to cerebral vasodilation can cause headaches. Based on our data, it is not possible to identify risk groups for whom wearing a mask in everyday working life would have particularly negative effects. Nevertheless, it seems reasonable that people with chronic respiratory diseases should use FFP2 masks with caution, as clinically significant changes in pO2 and pCO2 values have been reported for this group with mask use (3). In particular, less trained people (fast increase in heart rate) seem to experience symptoms such as dyspnoea, headaches, feeling hot, or dizziness with all mask types, especially with the FFP2 mask, sometimes independent of the grade of exertion. Based on the relationship shown between perceived exertion and the tightness of a mask seal, it cannot be ruled out that the measured increase in PtcCO2 with the FFP2 mask caused the high level of perceived exertion and subjective discomfort, although it remains unclear to what extent somatic or psychological factors play a role. Protective measures can only be sufficiently implemented in the workforce and the general population if they are widely accepted, and this should be taken into account when planning mask use in hospitals.
In summary, a short-term high workload while wearing the common mask types used in hospitals seems to have measurable but clinically irrelevant influence on the blood gases and vital parameters in people of working age who have no known underlying cardiopulmonary disease. Direct effects of an increase in CO2 on the described symptoms, or health risks from long-term mask wearing, cannot be ruled out but are rather unlikely given the described relationships.
Christian Georgi, Anja Haase-Fielitz, Daniel Meretz, Linda Gäsert, Christian Butter
Department of Cardiology, Immanuel Hospital Bernau, Brandenburg Heart Center (Georgi, Haase-Fielitz, Meretz, Gäsert, Butter) email@example.com
Medical School Brandenburg (MHB) Theodor Fontane, Bernau, Germany (Georgi, Haase-Fielitz, Meretz, Butter)
Faculty of Health Sciences (FGW) Brandenburg (Haase-Fielitz, Butter)
Institute of Social Medicine and Health Systems Research, Medical Faculty, Otto-von-Guericke University Hospital Madgeburg, Germany (Haase-Fielitz)
Conflict of interest statement
The authors declare that no conflict of interest exists.
Manuscript received on 15 June 2020, revised version accepted on 20 August 2020.
Translated from the original German by Dr. Veronica A. Raker.
Cite this as:
Georgi C, Haase-Fielitz A, Meretz D, Gäsert L, Butter C: The impact of commonly-worn face masks on physiological parameters and on discomfort during standard work-related physical effort. Dtsch Arztebl Int 2020; 117: 674–5.
|1.||Marais BJ, Sorrell TC: Pathways to COVID-19 ‚community protection‘. Int J Infect Dis 2020; 96: 496–9 CrossRef MEDLINE PubMed Central|
|2.||Süddeutsche Zeitung Digitale Medien: Ausatmen unterm Mundschutz: Ist das gefährlich? München: Süddeutscher Verlag, 24. April 2020; www.sueddeutsche.de/gesundheit/gesundheit-ausatmen-unterm-mundschutz-ist-das-gefaehrlich-dpa.urn-newsml-dpa-com-20090101-200424-99-817587 (last accessed on 08 June 2020).|
|3.||Kyung SY, Kim Y, Hwang H, Park JW, Jeong SH: Risks of N95 face mask use in subjects with COPD. Respir Care 2020; 65: 658–64 CrossRef MEDLINE|
|4.||Fikenzer S, Uhe T, Lavall D, et al.: Effects of surgical and FFP2/N95 face masks on cardiopulmonary exercise capacity (epub ahead of print, 6 July 2020). Clin Res Cardiol 2020; 109: 1–9 CrossRef|
|5.||Drechsler M, Morris J: Carbon dioxide narcosis. (Updated 20 December 2019). In: StatPearls; Treasure Island (FL): StatPearls Publishing; 2020; www.ncbi.nlm.nih.gov/books/NBK551620/ (last accessed on 8 June 2020)|
Effects of Face Masks on Physical Performance and Physiological Response during a Submaximal Bicycle Ergometer TestInternational Journal of Environmental Research and Public Health, 202210.3390/ijerph19031063
Is a Mask That Covers the Mouth and Nose Free from Undesirable Side Effects in Everyday Use and Free of Potential Hazards?International Journal of Environmental Research and Public Health, 202110.3390/ijerph18084344
Physio-metabolic and clinical consequences of wearing face masks—Systematic review with meta-analysis and comprehensive evaluationFrontiers in Public Health, 202310.3389/fpubh.2023.1125150
Ankara Üniversitesi Beden Eğitimi ve Spor Yüksekokulu SPORMETRE Beden Eğitimi ve Spor Bilimleri Dergisi, 202210.33689/spormetre.970305
Case Reports in Orthopedics, 202110.1155/2021/5600216
Deutsches Ärzteblatt international, 202110.3238/arztebl.m2021.0119
Pneumo News, 202010.1007/s15033-020-1939-6
The Effects of Wearing a Medical Mask on the Masticatory and Neck Muscle Activity in Healthy Young WomenJournal of Clinical Medicine, 202210.3390/jcm11020303
Limitations in evaluating COVID-19 protective face masks using open circuit spirometry systems: respiratory measurement mask introduces bias in breathing pressure and perceived respiratory effortPhysiological Measurement, 202310.1088/1361-6579/aca7ab