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Abstract
Background Widespread use of respiratory protection masks has become a critical component of public health response.
Objectives This systematic review synthesises the evidence on the acute physiological, cognitive and psychological impacts associated with different types of masks and provides an evidence map of research gaps.
Methods A comprehensive search from 2000 to 2023 was conducted across multiple databases (MEDLINE, EMBASE, Cochrane databases, Scopus and PubMed). An umbrella systematic overview was conducted for physiological outcomes using existing systematic reviews. We conducted de novo systematic reviews for cognitive and psychological outcomes. Pairs of independent reviewers determined eligibility, extracted data and assessed risk of bias. Certainty at an outcome level was appraised using the Grading of Recommendations Assessment, Development and Evaluation approach.
Results The search resulted in 13 370 potential citations, leading to the inclusion of nine systematic reviews for physiological outcomes (87 primary studies) and 10 primary studies for cognitive and psychological outcomes (3815 participants), with the majority of participants being healthy adults. Studies evaluating physiological outcomes demonstrated that various types of masks have little to no significant difference in heart rate (surgical mask (mean difference (MD): 0.96 (−1.01 to 2.93)), N95 mask (MD: 1.63 (−2.79 to 6.05)) and cloth mask (MD: −0.94 (−6.39 to 4.52))) or respiratory rate during rest or exercise (surgical mask (MD: −1.35 (−3.00 to 0.29)), N95 mask (MD: 0.10 (−3.10 to 3.29)) and cloth mask (MD: −2.57 (−6.44 to 1.29)) (low certainty for most outcomes)). Mask use may be associated with very small changes in minute ventilation (surgical mask (MD: −13.9 (−20.30 to −7.53)) and N95 mask (MD: −16.3 (−28.7 to −3.9))), tidal volume (surgical mask (MD: −0.14 (−0.23 to −0.05)) and N95 mask (MD: −0.10 (−0.33 to 0.13))), oxygen saturation (surgical mask (MD: −0.59% (−0.87 to −0.30)), N95 mask (MD: −0.35% (−0.75 to 0.05)) and cloth mask (MD: −0.50% (−1.23; 0.24))), carbon dioxide partial pressure (surgical mask (standardised MD (SMD): 1.17 (0.70 to 1.64)) and N95 mask (SMD: 0.43 (0.08 to 0.79))) and exercise performance (surgical mask (SMD: −0.12 (−0.39 to 0.15)), N95 mask (SMD: −0.42 (−0.76 to −0.08)) and cloth mask (SMD: −0.26 (−0.54 to 0.02)) (low certainty for most outcomes)). Studies evaluating cognitive outcomes showed mixed results. Some studies reported reduced mental workload, and others showed no significant effect or decreased performance. The impact on attention, errors and reaction time was variable. These studies were small and at moderate to high risk of bias. Evidence was insufficient to estimate the effect of mask use on psychological outcomes (claustrophobia, depression and anxiety) as these studies were small, non-longitudinal and at high risk of bias.
Conclusion This evidence map provides a comprehensive insight into the multifaceted impact of respiratory protection mask use, and highlights the limited certainty in the available body of evidence. This evidence map supports the development of future research agenda.
- Pulmonary Medicine
- PUBLIC HEALTH
- Systematic Reviews as Topic
- Evidence-Based Practice
Data availability statement
All data relevant to the study are included in the article or uploaded as supplementary information.
This is an open access article distributed in accordance with the Creative Commons Attribution Non Commercial (CC BY-NC 4.0) license, which permits others to distribute, remix, adapt, build upon this work non-commercially, and license their derivative works on different terms, provided the original work is properly cited, appropriate credit is given, any changes made indicated, and the use is non-commercial. See: http://creativecommons.org/licenses/by-nc/4.0/.
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WHAT IS ALREADY KNOWN ON THIS TOPIC
Prior research on the effects of face masks on physiological, cognitive and psychological outcomes during rest and exercise across different mask types and participant populations to date has been inconclusive.
WHAT THIS STUDY ADDS
The current evidence showed a slight change in minute ventilation, tidal volume, oxygen saturation, maximal oxygen consumption (VO2max), carbon dioxide partial pressure, lactate levels and exercise performance with mask use. There was a little to no significant difference in heart rate, stroke volume, cardiac output, blood pressure or respiratory rate. Studies evaluating cognitive and psychological outcomes showed mixed results. The study fills a crucial knowledge gap by systematically synthesising and analysing the current evidence on the acute physiological, cognitive and psychological impacts of face mask use during rest and exercise while providing a comprehensive understanding of the current knowledge regarding the effects of mask wearing on various health outcomes across different mask types and populations and highlighting areas of evidence gap to help guide future investigations in respiratory protection and public health.
HOW THIS STUDY MIGHT AFFECT RESEARCH, PRACTICE OR POLICY
More research is needed on the effects of mask wearing during physical activity to inform tailored recommendations for individuals and public health policies.
Introduction
In recent years, face masks became a crucial strategy to mitigate the transmission of infectious diseases, particularly respiratory viruses, causing a paradigm shift in the global public health landscape.1–3 This shift extends across diverse settings, including public transport, workplaces and recreational activities. During the early stages of the COVID-19 pandemic when vaccines were not widely available, wearing masks became one of the primary methods for protection against the disease.1 During this period, the selection of mask types has received considerable attention, driven by evidence suggesting that surgical masks and FFP2/N95 respirators offer superior particle filtration compared with cloth masks.4 While the efficacy of masks in reducing infection transmission is widely recognised,5 the surge in mask usage has raised concerns regarding their impact on health outcomes.6 Particularly, questions have arisen regarding their potential effects on respiratory and physiological parameters, especially during physical activity.7 8
Notably, numerous studies have examined the respiratory implications of prolonged mask use, revealing diverse findings.7 This is significant, especially given concerns regarding the increased breathing resistance and potential rebreathing of exhaled air associated with certain mask types, such as FFP2/N95 respirators and surgical masks. This effect may impact gas exchange dynamics leading to decreased oxygen intake (VO2max), oxygen saturation (SpO2) and increased carbon dioxide levels (PetCO2) especially during physical activity.9–12 However, existing literature presents conflicting data on the overall physiological effects of mask wearing during physical exertion.12–14 While some systematic reviews suggest modest impacts on physiological parameters like gas exchange and pulmonary function,12 others report minimal effect on physiological outcomes,15 with similar results noted for exercise performance.12 15
Mask use may also have an effect on various cognitive aspects, such as obscuring facial expressions, creating challenges with communication and increasing cognitive load.16 Few observational studies have touched on this, demonstrating increasing incidence of headache, attention deficit and difficulty in concentrating.17 Overall data about the impact of face mask use on cognitive function remain limited. Furthermore, the psychological impact of face mask use is another issue that warrants thorough exploration. Facial expressions provide visible cues and play a vital role in human connection and emotional communication. Alterations induced by masks in these cues may contribute to social and emotional challenges,18 potentially affecting mental well-being.
Considering the heightened focus on mask usage and its implications amid the COVID-19 pandemic, there has been an exponential rise in both individual studies and systematic reviews addressing this topic. However, the sheer volume of literature, coupled with the variability in findings and methodological quality among systematic reviews, poses a significant challenge for decision-makers. This abundance of information, often with conflicting results and varying levels of rigour, can obscure the actual state of evidence and potentially mislead those responsible for crafting public health guidelines and policies. Therefore, the objectives of our systematic review are to (1) synthesise the evidence on the acute physiological, cognitive and psychological impacts associated with different types of masks and (2) produce an evidence map19 that identifies evidence gaps and inform future research.
Methods
Study design
Due to the availability of multiple systematic reviews that addressed physiological outcomes, an umbrella systematic review (ie, an overview of systematic review) was conducted to identify and synthesise data from published systematic reviews. For the cognitive and psychological outcomes, no systematic reviews were identified and therefore de novo reviews were conducted. We followed a predefined published protocol without any upfront deviations20 and reported the methodology and findings in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses statement.21 22 The detailed PICO (Population, Intervention, Comparison, Outcome) questions addressed in this comprehensive systematic review are outlined in table 1.
Key questions (three questions addressing acute physiological, cognitive and psychological outcomes associated with mask use)
As our study followed a systematic review design and did not involve original research on human participants or direct patient involvement, we did not seek Institutional Review Board approval. However, we have rigorously maintained ethical standards in selecting, analysing and presenting existing literature.
Data sources and search strategy
A comprehensive search of several databases from 2000 to 28 July 2023 in any language was conducted. Databases included MEDLINE, EMBASE, Cochrane Central Register of Controlled Trials, Cochrane Database of Systematic Reviews, Scopus and PubMed. The search strategy was designed and conducted by a medical librarian with input from the study investigators. A controlled vocabulary supplemented with keywords was used to search various outcomes from wearing medical masks or air-purifying respirators (APR). The complete search strategies are available in online supplemental appendix A.
Supplemental material
Eligibility criteria
We included studies that (1) enrolled adults (aged 18 years and older), (2) evaluated surgical/medical masks, N95 masks/filtering facepiece respirators, military, and fire service APRs, and cloth masks, with no mask use, and (3) included at least one outcome of interest. (4) The study designs available include systematic review and meta-analysis for acute physiological outcomes (Q1), and comparative individual studies for cognitive (Q2) and psychological (Q3) outcomes. Factors such as duration of masking, activity level (at rest or with exercise) and altitude level (when relevant) were considered for subgroup analyses.
Study selection
Pairs of independent reviewers identified eligible studies by screening titles, abstracts and then full texts. Disagreements were resolved by consensus or arbitrated by a third reviewer, if necessary. For the systematic review addressing physiological outcomes, we only included reviews that had explicit inclusion and exclusion criteria and searched at least two databases. Inclusion was restricted to publications in the English language. In cases where multiple systematic reviews existed for a particular outcome, to avoid risk of overlapping evidence, studies were prioritised based on their methodological rigour, determined by the quality of included evidence and the overall methodological quality of the systematic review, followed by the highest number of included studies and then publication year. Notably, at least one systematic review was included for each intervention under investigation.
Data extraction and risk of bias assessment
Pairs of reviewers extracted data using a standardised, piloted, electronic form. We extracted data on patient characteristics, type of interventions and outcomes. Methodological quality of the systematic reviews was assessed using the AMSTAR instrument (a measurement tool to assess the methodological quality of systematic reviews). Pairs of reviewers working independently assessed the risk of bias using the modified Cochrane Collaboration tool for randomised clinical trials23 and the modified Newcastle-Ottawa Quality Assessment tool for observational studies24 for Q2 and Q3. Data regarding the risk of bias for Q1 were extracted from the systematic reviews. Disagreements were resolved by discussion or arbitrated by a third reviewer. We summarised the risk of bias for all domains to produce an overall risk of bias for every study.
Data synthesis and analysis
For continuous outcomes, we estimated the effect of interventions using the weighted mean difference or the standardised mean difference. For dichotomous outcomes, we estimated the relative risk. We used the I2 statistic and the Q statistic to assess heterogeneity. Evaluation for publication bias was not possible because of large heterogeneity that makes statistical tests for funnel plot symmetry unreliable.25 The certainty in evidence was rated using the approach of Grading of Recommendations Assessment, Development and Evaluation and narrative adaptations.26–28 Certainty from randomised controlled trials (RCT) was considered high but may be rated down for bias, indirectness, imprecision, inconsistency and publication bias. We rated down for inconsistency when we visually observed an important lack of overlap of CIs of individual studies. For imprecision, we rated down if sample size was <500 or the number of events was <100, or when CIs crossed the null effect with appreciable harm or benefit (<30 fewer outcomes or >30 more outcomes per 1000). For continuous outcome, we rated down for imprecision when the CI for the effect size crossed the null, except when the sample size was >800. We created a visual representation of all study outcomes (quantitative and qualitative) in the form of an evidence map. An evidence map shows the overall effects of mask use along with the risk of bias and certainty in these effects, helping decision-makers understand the possible benefits and gaps in research.19 29
Patient and public involvement
We did not involve patients or the public in the design, conduct, reporting and dissemination plans of this study.
Results
Literature search results
The electronic search yielded 13 370 potentially relevant citations, of which nine systematic reviews6 7 12 15 30–34 including 87 primary individual studies (74 RCTs, 9 non-RCTs and 4 observational studies) enrolling 3404 participants were included to assess the impact of respiratory protection mask use on acute physiological outcomes, with the majority of participants being healthy adults (86.6%), followed by adults with chronic obstructive pulmonary disease (COPD; 9.2%), and healthy children (3.1%). Additionally, one systematic review included 42 pregnant women. Additionally, 10 primary individual studies (2 RCTs,35 36 1 non-randomised controlled study37 and 7 observational studies17 38–43) involving 411 healthy participants were included to assess the impact of respiratory protection mask use on cognitive and psychological outcomes. The screening process is illustrated in figure 1, and the key characteristics of the selected studies are summarised in online supplemental tables 1 and 2, while the methodological qualities of the included studies are summarised in online supplemental table 3 (comparative observational studies) and online supplemental table 4 (randomised clinical trials).
Supplemental material
Flow chart. PRISMA, Preferred Reporting Items for Systematic Reviews and Meta-Analyses.
Outcomes
Acute physiological impact of respiratory protection mask use
The impact of respiratory protection mask use on acute physiological responses was extensively assessed across numerous systematic reviews and studies with low to very low certainty evidence.
Cardiovascular responses
Heart rate
Seven reviews reported on the impact of mask use on heart rate,6 12 15 30–33 out of which we prioritised two systematic reviews based on their methodological rigour, number of included studies and recent publication time.12 32 Wearing masks may cause little to no difference in heart rate compared with no mask in healthy adults or patients with COPD. In a subgroup analysis by exercise state, no significant difference was noted with mask wearing in healthy adults during the progressive exercise state; however, a slight increase in heart rate was noted during steady exercise state. Meta-analysis results are presented in table 2.
Effect of respiratory protection mask use on cardiovascular responses and certainty of evidence
Cardiac output
An analysis from one systematic review15 showed no significant difference on stroke volume or cardiac output with mask use compared with no mask in healthy adults. Meta-analysis results are presented in table 2.
Blood pressure
Four systematic reviews examined the impact of mask use on blood pressure,6 15 31 32 out of which we prioritised three systematic reviews based on their methodological rigour and number of included studies.15 31 32 Wearing masks was associated with little to no difference in systolic, diastolic and mean arterial blood pressure compared with no mask in healthy adults or patients with COPD. In a subgroup analysis by exercise state, no significant difference was noted in systolic or diastolic blood pressure in patients with COPD. Meta-analysis results are presented in table 2.
Ventilatory responses
Respiratory rate
Seven reviews reported the impact of mask use on respiratory rate (RR),6 12 15 30–33 out of which we prioritised two systematic reviews based on their methodological rigour, number of included studies and recent publication time.12 32 Wearing masks may cause little to no difference in RR compared with no mask in healthy adults or patients with COPD. In a subgroup analysis by exercise state, no significant difference was noted in RR in healthy adults during the different exercise states. Meta-analysis results are presented in table 3.
Effect of respiratory protection mask use on ventilatory responses and certainty of evidence
Minute ventilation
Six systematic reviews6 12 15 30 32 33 reported this outcome, out of which we prioritised two systematic reviews based on their methodological rigour, number of included studies and recent publication time.12 32 Wearing masks was associated with a reduction in minute ventilation (VE) in healthy adults, with little to no difference in VE noted with mask use in patients with COPD. In a subgroup analysis by exercise state, wearing masks was associated with a reduction in VE in healthy adults during progressive exercise states with little to no difference noted during the steady exercise state. Meta-analysis results are presented in table 3.
Tidal volume
Four systematic reviews6 12 15 33 reported data regarding the impact of mask use on tidal volume (VT), out of which we prioritised one systematic review based on methodological rigour, number of included studies and recent publication time.12 Wearing surgical masks was associated with a reduction in VT in healthy adults compared with no mask. However, little to no difference was observed with N95 mask use. In a subgroup analysis by exercise state, wearing masks was associated with a reduction in VT in healthy adults during progressive exercise states with little to no difference noted during the steady exercise state. Meta-analysis results are presented in table 3.
Carbon dioxide ventilation equivalent (VE/VCO2)
An analysis from one systematic review12 showed a reduction in VE/VCO2 with surgical mask use compared with no mask in healthy adults. In a subgroup analysis by exercise state, little to no difference was noted in VE/VCO2 in healthy adults during the different exercise states. Meta-analysis results are presented in table 3.
Metabolic responses
Oxygen saturation
Eight systematic reviews6 7 12 15 30–33 reported this outcome, out of which we prioritised two systematic reviews based on their methodological rigour, number of included studies and recent publication time.12 32 Wearing surgical masks was associated with a small reduction in oxygen saturation in healthy adults and patients with COPD, with little to no difference noted in oxygen saturation with N95 or cloth mask use. In a subgroup analysis by exercise state, a small reduction in oxygen saturation was noted in healthy adults during the different exercise states. Meta-analysis results are presented in table 4.
Effect of respiratory protection mask use on metabolic responses and certainty of evidence
End-tidal oxygen partial pressure
An analysis from one systematic review12 showed a reduction in end-tidal oxygen partial pressure (PetO2) with mask use. Meta-analysis results are presented in table 4.
Oxygen uptake
Three systematic reviews6 12 30 reported data regarding the impact of mask use on oxygen uptake, out of which we prioritised two systematic reviews based on their methodological rigour, number of included studies and recent publication time.12 32 Wearing masks was associated with a decrease in oxygen uptake (VO2) compared with no mask in healthy adults. In a subgroup analysis by exercise state, a small reduction in oxygen uptake was noted in healthy adults during the different exercise states. Meta-analysis results are presented in table 4.
Muscle oxygenation
An analysis from one systematic review15 showed wearing face masks was associated with little to no significant difference in muscle oxygenation during exercise compared with no mask use in adult participants. Meta-analysis results are presented in table 4.
Carbon dioxide
Three systematic reviews6 7 30 reported this outcome, out of which we prioritised two systematic reviews based on the methodological rigour, number of included studies and publication time.7 12 Wearing surgical masks was associated with a small reduction in VCO2 in healthy adults, with little to no significant difference noted with N95 mask use. In a subgroup analysis by exercise state, wearing an N95 mask was associated with a slight increase in carbon dioxide in healthy adults during the different exercise states. Meta-analysis results are presented in table 4.
End-tidal CO2
Three systematic reviews12 15 32 reported the impact of mask use on end-tidal carbon dioxide, out of which we prioritised two systematic reviews based on their methodological rigour, number of included studies and recent publication time.12 32 Wearing masks was associated with an increase in end-tidal CO2 in healthy adults with little to no significant difference noted in patients with COPD. In a subgroup analysis by exercise state, a slight increase in end-tidal CO2 was noted in healthy adults during the different exercise states. Meta-analysis results are presented in table 4.
Lactate
Three systematic reviews12 15 32 reported this outcome, out of which we prioritised two systematic reviews based on their methodological rigour, number of included studies and recent publication time.12 32 Wearing masks was associated with little to no significant difference in lactate levels in healthy adults; however, a small reduction in lactate level was noted in patients with COPD. In a subgroup analysis by exercise type, a small decrease in lactate level was noted in healthy adults during the progressive exercise state with little to no significant difference noted during steady exercise state. Meta-analysis results are presented in table 4.
Exercise performance
Exercise performance
Four systematic reviews12 15 30 32 assessed the impact of mask use on exercise performance, out of which we prioritised two systematic reviews based on their methodological rigour, number of included studies and recent publication time.12 32 N95 mask use was associated with a slight reduction in exercise performance in healthy adult’s rate compared with no mask, with little to no significant difference noted with surgical and cloth mask use in healthy adults and patients with COPD. In a subgroup analysis by exercise type, a small decrease in exercise performance was noted with mask use in healthy adults during the progressive exercise state with little to no significant difference noted during the steady exercise state. Meta-analysis results are presented in table 5.
Effect of respiratory protection mask use on exercise performance and certainty of evidence
Time to exhaustion and perceived exertion
Three systematic reviews12 15 34 reported this outcome. We prioritised two systematic reviews based on their methodological rigour, number of included studies and publication time.12 34 Wearing surgical masks was associated with higher perceived exertion (rating of perceived exertion) scores in healthy adults compared with no mask use; however, little to no significant difference was noted with N95 or cloth mask use. Additionally, a slight reduction in time to exhaustion was noted with the use of face masks compared with the no mask. Meta-analysis results are presented in table 5.
Thermal sensation and facial skin temperature
Two systematic reviews6 12 reported this outcome. Wearing masks was associated with an increase in thermal sensation compared with no mask use in healthy adults. In a subgroup analysis by exercise type, an increase in thermal sensation was noted with mask use in healthy adults during different exercise states. Additionally, facial skin temperature significantly increased with mask use; however, no significant difference was observed in subjective ratings of heat perception between mask and no mask groups. Meta-analysis results are presented in table 5.
Cognitive influence of respiratory protection mask use
Studies examining the impact of face mask use on cognitive function during exercise have produced mixed results with low to very low certainty of evidence. Some studies, such as Braun-Trocchio et al37 and Slimani et al,41 suggest potential benefits, including improved cognitive function and increased internal focus among mask wearers. However, other research, like that by Deng et al,35 indicates a reduction in mental workload but lower performance in terms of accuracy. Contrary findings were reported by Jahangiri et al39 and Grimm et al,36 no significant differences in cognitive performance were observed between mask types or during exercise. Additionally, Tornero-Aguilera and Clemente-Suárez43 found no effects on mental fatigue or reaction time with surgical face mask use. Notably, Ipek et al17 identified a higher rate of attention deficit among N95 respirator wearers compared with face mask wearers, suggesting potential drawbacks associated with certain mask types. Overall, while some studies suggest potential cognitive benefits, others report no significant effects or even adverse outcomes, highlighting the complexity of the relationship between mask use and cognitive function during exercise. Results are presented in table 6.
A narrative review of the available evidence on the effect of mask use on cognitive performance and psychological outcomes
Psychological impact associated with respiratory protection mask use
The psychological impact of respiratory protection mask use, particularly regarding claustrophobia and mental health outcomes, has been investigated in several studies with varying results and limited certainty of evidence. A study conducted by Chong et al38 revealed that 3% of healthcare workers experienced claustrophobia while wearing face masks. This percentage was found to be similar for both N95 respirators and surgical masks. However, Khalid et al40 discovered higher rates of claustrophobia in the N95 group. On the other hand, Su et al42 observed no significant difference in depression or anxiety rates between healthcare workers wearing surgical masks and those using N95 respirators. Results are presented in table 6.
Evidence map
Figure 2 provides an evidence map illustrating the main findings on various respiratory protection mask use. The map suggests a lack of comprehensive assessment regarding the acute physiological, cognitive and psychological impacts of different mask types. Physiological effects showed minimal changes, particularly in ventilation and oxygen levels. However, evidence on cognitive and psychological outcomes varied and was constrained by study limitations and various biases. Overall, the certainty of evidence ranged from very low to low for most interventions, with no high-certainty evidence available. Furthermore, there is insufficient evidence regarding the impact of mask use on different work groups, duration of masking or the effects of mask use at high altitude levels.
Evidence map demonstrating the availability of evidence and its quality for the various physiological, cognitive and psychological outcomes associated with mask use. COPD, chronic obstructive pulmonary disease.
Discussion
To our knowledge, this is the first evidence map to examine the acute physiological, cognitive and psychological impacts of different mask types during rest and exercise. Similar to previously reported studies,12 15 30 our study revealed modest impacts on variables such as ventilation and oxygen levels; however, the overall evidence remains inconclusive, with majority of studies indicating minimal changes in cardiovascular, ventilatory and metabolic responses, and exercise performance associated with mask use during both rest and physical activity. We noted variations in findings across different mask types and participant populations. For instance, while surgical masks and cloth masks showed no significant impact on physiological parameters, N95 respirators were associated with modest changes in VE, VT, oxygen saturation, carbon dioxide levels and exercise performance. While some of these parameters revealed statistical differences between those wearing and not wearing face masks, the level of change was small, and most values remained in the normal range.
Studies examining the cognitive effects of mask use during exercise yielded heterogeneous results, reflecting the multifaceted nature of cognitive function. While some studies suggested potential benefits in terms of improved cognitive function and increased internal focus among mask wearers, others reported no significant effects or even adverse outcomes. Communication challenges and perceptual shifts induced by mask wearing may contribute to variations in cognitive performance during physical activity. However, methodological limitations and inconsistencies across studies warrant cautious interpretation of these findings. Future research should aim to clarify the relationship between mask use and cognitive function, considering factors such as mask type, duration of use and activity level.
Similarly, the psychological impact of mask use remains a complex and understudied area. While some studies report elevated levels of claustrophobia among mask wearers, others find no significant differences in depression or anxiety rates compared with non-mask wearers. These conflicting findings highlight the need for more rigorous studies assessing the psychological effects of mask use over time, considering individual factors such as personality traits, coping mechanisms and pre-existing mental health conditions.
Strengths and limitations
The strengths of this systematic review relate to the comprehensive search and rigorous methodological approach in addition to the inclusion of diverse study designs and populations. Moreover, by synthesising evidence from multiple systematic reviews and primary studies, we provided a comprehensive overview of the current state of knowledge on mask-related health outcomes.
Despite our efforts to include high-quality studies across various settings and populations, the increased heterogeneity across studies and the methodological quality of the current available studies have led to lower certainty of evidence. The exclusion of non-English language studies and limiting our search strategies only to studies published after 2000 and the focus on acute rather than long-term effects may have limited the generalisability of the findings, although the inclusion of systematic review that included studies published before 2000 may have limited the impact of this. Additionally, most of the data regarding the psychological and cognitive outcomes were driven from studies performed on healthcare workers which may limit its generalisability to the public.
Research implications
Additionally, the predominance of observational studies and the limited number of high-quality RCTs underscore the need for more robust research in this area. Studies need to have a longer follow-up to address the short- and long-term effects of different types of face mask, fit and duration of use on different physiological, cognitive and psychological parameters. Future studies should leverage previously validated and standardised assessment tools to assess the cognitive and psychological outcomes. Qualitative research is critical to better understand barriers to face mask use and perceptions of individuals in different contexts, cultural backgrounds and professional roles.
Conclusion
This evidence map provides a comprehensive insight into the multifaceted impact of respiratory protection mask use in addition to the limited certainty in the currently available body of evidence. The evidence map approach is intended to facilitate the development of future research agenda.
Data availability statement
All data relevant to the study are included in the article or uploaded as supplementary information.
Ethics statements
Patient consent for publication
Ethics approval
Not applicable.
References
Supplementary materials
Supplementary Data
This web only file has been produced by the BMJ Publishing Group from an electronic file supplied by the author(s) and has not been edited for content.
Footnotes
X @BasharHasanMD
Contributors WF, MW, BDJ and MHM conceived and planned the study protocol and design. MW is the guarantor. WF, MFA, BH, EHL, FF and WYE participated in data extraction and synthesis. WF, MW, BDJ, MHM, MFA, BH and GT contributed to the interpretation of the results. WF and MFA took the lead in writing the manuscript. All authors provided critical feedback and helped shape the research, analysis and manuscript.
Funding This work was supported by a grant from the Federal Aviation Administration (Task No 01-2023: FAA/CAMI-M).
Disclaimer The funders had no role in study design, data collection, analysis, decision to publish, or preparation of the manuscript.
Competing interests None declared.
Patient and public involvement Patients and/or the public were not involved in the design, or conduct, or reporting, or dissemination plans of this research.
Provenance and peer review Not commissioned; externally peer reviewed.
Supplemental material This content has been supplied by the author(s). It has not been vetted by BMJ Publishing Group Limited (BMJ) and may not have been peer-reviewed. Any opinions or recommendations discussed are solely those of the author(s) and are not endorsed by BMJ. BMJ disclaims all liability and responsibility arising from any reliance placed on the content. Where the content includes any translated material, BMJ does not warrant the accuracy and reliability of the translations (including but not limited to local regulations, clinical guidelines, terminology, drug names and drug dosages), and is not responsible for any error and/or omissions arising from translation and adaptation or otherwise.