Effect of Cloth Masks and N95 Respirators on Maximal Exercise Performance in Collegiate Athletes

his study compared exercise performance and comfort while wearing an N95 ltering facepiece respirator (N95), cloth mask, or no intervention control for source control during a maximal graded treadmill exercise test (GXT). Twelve Division 1 athletes (50% female, age = 20.1 1.2, BMI = 23.5 1.6) completed GXTs under three randomized conditions (N95, cloth mask, control). GXT duration, heart rate

This study compared exercise performance and comfort while wearing an N95 ltering facepiece respirator (N95), cloth mask, or no intervention control for source control during a maximal graded treadmill exercise test (GXT). Twelve Division 1 athletes (50% female, age = 20.1 1.2, BMI = 23.5 1.6) completed GXTs under three randomized conditions (N95, cloth mask, control). GXT duration, heart rate (HR), respiration rate (RR), transcutaneous oxygen saturation (SpO 2), transcutaneous carbon dioxide (TcPCO 2), rating of perceived exertion (RPE), and perceived comfort were measured. Participants ran signi cantly longer in control (26.06 min) versus N95 (24.20 min, p= 0.03) or cloth masks (24.06 min,p= 0.04). No differences occurred in the slope of HR or SpO 2 across conditions (p> 0.05). TcPCO 2decreased faster in control (B = 0.89) versus N95 (B = 0.14, p= 0.02) or cloth masks (B = 0.26,p= 0.03). RR increased faster in control (B = 8.32) versus cloth masks (B = 6.20,p= 0.04). RPE increased faster in the N95 (B = 1.91) and cloth masks (B = 1.79) versus control (B = 1.59,p< 0.001 andp= 0.05, respectively). Facial irritation/itching/pinching was higher in the N95 versus cloth masks, but sweat/moisture buildup was lower (p< 0.05 for all). Wearing cloth masks or N95s for source control may impact exercise performance, especially at higher intensities. Signi cant physiological differences were observed between cloth masks and N95s compared to control, while no physiological differences were found between cloth masks and N95s; however, comfort my differ. Keywords:COVID-19; face covering; graded exercise test; personal protective equipment 1. Introduction Aligned with April 2020 CDC recommendations to facilitate source control, universal masking was adopted by many athletic associations including the National Collegiate Athletic Association (NCAA) [1] and the Pennsylvania Interscholastic Athletic Association (PIAA) [2]. The recommendations for athlete source control have often included masking during strenuous activity, times of game preparation, recovery, and in some cases, athletic competitions [1,2]. While mask mandates and guidelines for the general population and athletes have uctuated based on community disease prevalence, hospitalization and death rates, and vaccine status over the course of the pandemic, many athletes are still

The recommendations for athlete source control have often included masking during strenuous activity, times of game preparation, recovery, and in some cases, athletic competitions [1,2]. While mask mandates and guidelines for the general population and athletes have uctuated based on community disease prevalence, hospitalization and death rates, and vaccine status over the course of the pandemic, many athletes are still wearing masks of various types during practice, training, and competitions. For example, Int. J. Environ. Res. Public Health2022,19, 7586.

Int. J. Environ. Res. Public Health2022,19, 7586 2 of 11 the Medical Advisory Group for the Atlantic Coast Conference (ACC) did not mandate mask wearing during activity, but some ACC teams such as women's volleyball during the 2020/21 season elected to wear masks for source control during competition. Similarly, the Big 10 volleyball teams also elected to wear masks during competition. While masking in the face of disease is not a novel approach to mitigate viral spread, such widespread use, including masking during strenuous athletic activity, has an unknown effect on physiology and performance. Further complicating the problem, individuals wore a wide variety of products to achieve the desired source control included masks (often referred to as barrier face coverings, cloth masks, face masks, facial coverings, etc., in different contexts or to refer to masks made of different materials) and respirators (e.g., N95 ltering facepiece respirators (N95s)) worn for the purpose of source control. However, the differential impact of using these various types of products for source control on athletic performance is unknown. Traditionally, the research in this area has focused on the impact of wearing t-tested N95s or other National Institute for Occupational Safety and Health (NIOSH)-approved respiratory protection devices during moderate intensity occupational tasks [3–6]. While some small physiological performance changes have been noted in these studies, none have found differences that are clinically relevant to user safety (the main concern in this type of occupational research), few were focused on performance decrements at high intensities important to athletes, and fewer still have focused on t- tested respirators rather than on masks or respirators used as source control such as those being recommended for public use during the COVID-19 pandemic [6–10]. In athletics, not only is disease transmission risk and source control a concern when making mask use recommendations, exercise performance and safety implications must also be considered. While it is known from previous research that exercise performance time is linearly and negatively related to inhalation resistance (induced by respirators and masks) [3,11,12], it is still unclear how these assumptions will affect athlete performance in real-world settings or

risk and source control a concern when making mask use recommendations, exercise performance and safety implications must also be considered. While it is known from previous research that exercise performance time is linearly and negatively related to inhalation resistance (induced by respirators and masks) [3,11,12], it is still unclear how these assumptions will affect athlete performance in real-world settings or across different mask types. Since the start of the COVID-19 pandemic, only one study has looked at wearing a cloth mask during activity, concluding that cloth masks reduced graded exercise test (GXT) time by 14% compared to no mask. However, the study sample of 31 participants were not elite athletes and the study did not include a comparison to any other type of source control product, such as an N95 respirator [9]. These limitations in external validity are important to address prior to translating the results to recommendations speci cally for athletes while also considering performance across mask types. Accordingly, the purpose of this study is to compare the physiological and performance effects of three source control interventions (N95, cloth mask, and no intervention) during high intensity graded exercise in elite athletes. The results will have practical implications for understanding the ability for individuals to perform high-intensity activities while wearing an N95 or cloth mask for source control. 2. Materials & Methods 2.1. Participants Recruitment of all volunteer participants occurred through a search of scholarship division 1 athletes at the University of Pittsburgh. Initial contact was made with all potential participants via word of mouth. Athletes interested in participation attended a session where the details of the study and their participation were explained and eligibility criteria were examined. If the athletes remained eligible and interested, they were asked to sign an informed consent document prior to study initiation. Participation included a screening followed by three separate visits to the University of Pittsburgh Fitzgerald Field House Gymnasium where testing was completed across six weeks in May and June 2020. Eligible participants were (1) between 18 and 24 years of age, (2) a current NCAA athlete, and (3) free from contraindications for

an informed consent document prior to study initiation. Participation included a screening followed by three separate visits to the University of Pittsburgh Fitzgerald Field House Gymnasium where testing was completed across six weeks in May and June 2020. Eligible participants were (1) between 18 and 24 years of age, (2) a current NCAA athlete, and (3) free from contraindications for maximal treadmill exercise testing such as musculoskeletal injury, cardiopulmonary disease, taking medications that affect the heart rate response to exercise, or considered to be a high-risk population according to CDC COVID-19 guidelines. No nancial reimbursement was provided to participants.

Int. J. Environ. Res. Public Health2022,19, 7586 3 of 11 Sample characteristics are presented in Table. Participants were 50% female, had an average age of 20.1 1.2 years, weight of 68.7 9.1 kg, height of 1.7 0.1 m, and BMI of 23.5 1.6 kg/m 2 . Participants were student athletes distributed across gymnastics (n= 2, 16.7%), wrestling (n= 5, 41.7%), soccer (n= 4, 33.3%), and swimming (n= 1, 8.3%). Table 1.Sample characteristics (n= 12). Age (years) 20.1 1.2 Sex Female 6 (50%) Male 6 (50%) Weight (kilograms) 68.7 9.1 Height (meters) 1.7 0.1 Body Mass Index (kg/m 2 ) 23.5 1.6 Sport Gymnastics (F) * 2 (16.7%) Wrestling (M) * 5 (41.7%) Soccer (F) * 4 (33.3%) Swimming (M) * 1 (8.3%) All data are presented as either mean standard deviation or frequency (proportion) as necessary. * M and F indicate male or female sports teams/participants. 2.2. Ethical Considerations Ethical approval was obtained from the University of Pittsburgh Human Protection Research Of ce (Study ID# 20080095). All participants signed an informed consent prior to study participation. 2.3. Graded Treadmill Exercise Test All participants performed three separate treadmill GXTs (one for each mask condition)at the University of Pittsburgh Fitzgerald Field House Gymnasium using a motorized treadmill (Woodway, 4Front, Waukesha, WI, USA). Prior to each GXT, the participant sat quietly for 5 min (rest stage), followed by a 5-min walking period (walking stage, 5.31 km per hour (km/h) and 0% grade). After completion of the walking stage, the participant moved onto a modi ed Astrand Running Protocol for maximal treadmill exercise [13]. This protocol consisted of a jogging warm-up for 5 min followed by 3-min stages of constant treadmill speed and progressively higher grade (2.5% increase each stage). The jogging warm-up (80% of testing speed) and testing running speeds (10.5–16 km/h) were determined based on the participant's self-reported 2- or 3-mile running time. Verbal motivation was used to provide positive encouragement to the participants to promote continued effort. While the motivation provided was not recorded, it was provided in an anecdotally similar way across all experimental sessions. After indicating that they had

of testing speed) and testing running speeds (10.5–16 km/h) were determined based on the participant's self-reported 2- or 3-mile running time. Verbal motivation was used to provide positive encouragement to the participants to promote continued effort. While the motivation provided was not recorded, it was provided in an anecdotally similar way across all experimental sessions. After indicating that they had reach terminal fatigue, the participants were instructed to remove themselves from the moving treadmill to the side rails which marked the completion of the GXT. All physiological and perceptual parameters were recorded within 10 s of GXT termination to serve as the end-exercise values. After test termination, all participants performed a 5-min walking cool-down on the treadmill (5.31 km/h, 0% grade) followed by a ve-minute seated recovery period. Heart rate (HR) and respiratory rate (RR) were measured continuously throughout the exercise test using the validated Hexoskin smart shirt (Hexoskin Pro Shirt, Carre Tech- nologies Inc., Montreal, QC, Canada) [14–16]. Transcutaneous oxygen saturation (SpO2) and transcutaneous carbon dioxide (TcPCO2) was measured continuously throughout the testing using a transcutaneous ear lobe sensor validated for use during graded treadmill exercise (TOSCA 500, Radiometer Medical, Denmark, Sweden) [17]. Ratings of perceived exertion (RPE) were measured on a scale from 0 (extremely easy) to 10 (extremely hard) us- ing the validated OMNI rating of perceived exertion pictorial scale [18]. All variables were recorded manually during the last 30 s of each timed protocol stage (rest, walk, exercise, etc.). All sensors and the smart shirt were tted to the participants using the associated

Int. J. Environ. Res. Public Health2022,19, 7586 4 of 11 manufacturer instructions for sizing, preparation, and attachment prior to beginning the measurement and exercise protocol. 2.4. Experimental Conditions Each participant performed three trials which included the following source control interventions: no intervention, cloth mask, and a NIOSH-approved N95 respirator. The cloth mask was the same brand and style between participants: triple-layer 100% cotton face mask with elastic ear loops (model: #661692, Old Navy, San Francisco, CA, USA). The N95 used was the same model for all tests (1860, 3M, St Paul, MN, USA). A user seal check of the N95 was performed by each participant prior to beginning each test [19]. No formal t tests were completed because the intent was to examine the use of the N95 as source control. After each trial, the N95s were thrown away and the cloth masks were machine washed prior to reuse. During each trial, participants were not permitted to touch or readjust their respective mask or N95. Athletes were randomly assigned and counterbalanced to one of six experimental sequences to minimize any order effect. There was a minimum 48-h wash-out period between each testing day for all participants. 2.5. Subjective Comfort and Wearing Experience Following each cloth mask and N95 trial, the participants were asked to provide feedback regarding their subjective comfort as well as the perceived wearing experience using the validated Respirator Comfort, Wearing Experience, and Function Instrument (R-COMFI) [20]. While this instrument was designed for use in healthcare workers, most of the questions translate well across populations except for the questions related to function during healthcare speci c work (#17–21) [20]. As such, those questions were omitted from this study. 2.6. Experimental Controls Prior to each GXT, participants were asked to record nutritional intake as well as physical activity for that day. Each participant was encouraged to reproduce their intake and physical activity pattern as closely as possible prior to each trial. Further, each participant was encouraged to wear the same footwear for each of their respective trials. 2.7. Statistical Analysis Descriptive statistics were used to describe the demographic characteristics

to record nutritional intake as well as physical activity for that day. Each participant was encouraged to reproduce their intake and physical activity pattern as closely as possible prior to each trial. Further, each participant was encouraged to wear the same footwear for each of their respective trials. 2.7. Statistical Analysis Descriptive statistics were used to describe the demographic characteristics of the sample population presented in Table. The use of linear mixed models with post-hoc Bonferroni adjustment was employed to compare the differences in GXT termination time across the three source control interventions of interest (no intervention, N95, and cloth mask) (Figure). Linear regression models were used to estimate the simple slope of each of the ve physiological parameters measured (heart rate, respiration rate SpO2, TcPCO2, and RPE) over time during the exercise test. Further, moderation by mask type was explored by including the interaction between time and a dummy variable indicating the intervention condition (i.e., 1, 2, 3) into the regression model to test for the pairwise differences between the estimated regression slopes across the three intervention conditions. Along with the simple linear regression results, Table Table with apvalue of the difference between the prediction of termination time by intervention condition. The column labeled “pvalue of difference” indicates whether the physiological variable over time is signi cantly different in each intervention condition. Ifpvalues in this column are below 0.05, signi cant moderation is indicated. The variable of time was centered for the models. All models controlled for the effects of participant age, height, weight, and BMI.

Int. J. Environ. Res. Public Health2022,19, 7586 5 of 11Int. J. Environ. Res. Public Health 2022, 19, x FOR PEER REVIEW 5 of 12 was explored by including the interaction between time and a dummy variable indicat- ing the intervention condition (i.e., 1, 2, 3) into the regression model to test for the pair- wise differences between the estimated regression slopes across the three intervention conditions. Along with the simple linear regression results, Table 2 includes the results of the moderation analysis. Table 2 shows the estimated regression coefficients for each intervention condition along with a p value of the difference between the prediction of termination time by intervention condition. The column labeled “p value of difference” indicates whether the physiological variable over time is significantly different in each intervention condition. If p values in this column are below 0.05, significant moderation is indicated. The variable of time was centered for the models. All models controlled for the effects of participant age, height, weight, and BMI. Figure 1. Graded exercise test termination time across three conditions. Note: error bars are 95% CI around the mean. * = significate difference in test termination time compared to no intervention (p < 0.05). Table 2. Comparison of linear physiological and perceived exertion responses across conditions. Dependent Variable Simple Slope Over Time p Value of Difference in Regression Slope B Beta Standard Error p Value R 2 (Adjusted) No Mask vs. N95 No Mask vs. Cloth Mask N95 vs. Cloth Mask Heart Rate N95 22.67 0.88 1.24 <0.001 0.81 0.54 0.25 0.55 Cloth Mask 23.35 0.88 1.15 <0.001 0.84 No Intervention 21.10 0.90 1.16 <0.001 0.83 Respiration Rate N95 7.61 0.84 0.57 <0.001 0.76 0.38 0.04 0.19 Cloth Mask 6.20 0.76 0.61 <0.001 0.63 No Intervention 8.32 0.85 0.58 <0.001 0.75 SpO 2 N95 −0.58 −0.62 0.09 <0.001 0.35 0.36 0.16 0.59 Cloth Mask −0.64 −0.69 0.08 <0.001 0.52 No Intervention −0.47 −0.48 0.09 <0.001 0.32 TcPCO 2 Figure 1. Graded exercise test termination time across three conditions. Note: error bars are 95% CI around the mean. * = signi cate difference in test

No Intervention 8.32 0.85 0.58 <0.001 0.75 SpO 2 N95 −0.58 −0.62 0.09 <0.001 0.35 0.36 0.16 0.59 Cloth Mask −0.64 −0.69 0.08 <0.001 0.52 No Intervention −0.47 −0.48 0.09 <0.001 0.32 TcPCO 2 Figure 1. Graded exercise test termination time across three conditions. Note: error bars are 95% CI around the mean. * = signi cate difference in test termination time compared to no intervention (p< 0.05). Table 2.Comparison of linear physiological and perceived exertion responses across conditions. Dependent Variable Simple Slope Over Time pValue of Difference in Regression Slope B Beta Standard Error pValue R 2 (Adjusted) No Mask vs. N95 No Mask vs. Cloth Mask N95 vs. Cloth Mask Heart Rate N95 22.67 0.88 1.24 <0.001 0.81 0.54 0.25 0.55 Cloth Mask 23.35 0.88 1.15 <0.001 0.84 No Intervention 21.10 0.90 1.16 <0.001 0.83 Respiration Rate N95 7.61 0.84 0.57 <0.001 0.76 0.38 0.04 0.19 Cloth Mask 6.20 0.76 0.61 <0.001 0.63 No Intervention 8.32 0.85 0.58 <0.001 0.75 SpO2 N95 0.58 0.62 0.09 <0.001 0.35 0.36 0.16 0.59 Cloth Mask 0.64 0.69 0.08 <0.001 0.52 No Intervention 0.47 0.48 0.09 <0.001 0.32 TcPCO2 N95 0.14 0.07 0.26 0.60 0.14 0.02 0.03 0.72 Cloth Mask 0.26 0.13 0.21 0.23 0.19 No Intervention 0.89 0.51 0.18 <0.001 0.33 RPE N95 1.91 0.96 0.05 <0.001 0.92 <0.001 0.05 0.23 Cloth Mask 1.79 0.95 0.06 <0.001 0.90 No Intervention 1.59 0.92 0.08 <0.001 0.84 Abbreviations: B = regression coef cient, Beta = standardized regression coef cient, SpO2= transcutaneous oxygen saturation, TcPCO2= transcutaneous carbon dioxide, RPE = rating of perceived exertion. All models controlled for the effect of subject age, height, weight, and BMI. Subjective responses to the R-COMFI questionnaire were summarized using descrip- tive statistics for the N95 and cloth mask (Table). Scores for each question were compared using paired samplet-tests. The alpha level was set at 0.05 for all comparisons and all analyses were performed in the Statistical Package for the Social Sciences (SPSS) v.28.

The study investigates the impact of masks on exercise performance in collegiate athletes.