Maximal exercise outcomes with a face mask: the effects of gender and age differences on cardiorespiratory responses

The real bacterial filtration efficiency to evaluate the effective protection of facemasks used for the prevention of respiratory diseases

The real protection offered by facemasks to control the transmission of respiratory viruses is still undetermined. Most of the manufacturing regulations, as well as scientific studies, have focused on studying the filtration capacity of the fabrics from which they are made, ignoring the air that escapes through the facial misalignments, and which depends on the respiratory frequencies and volumes. The objective of this work was to define a Real Bacterial Filtration Efficiency for each type of facemask, considering the bacterial filtration efficiency of the manufacturers and the air that passes through them. Nine different facemasks were tested on a mannequin with three gas analyzers (measuring inlet, outlet, and leak volumes) inside a polymethylmethacrylate box. In addition, the differential pressure was measured to determine the resistance offered by the facemasks during the inhalation and exhalation processes. Air was introduced with a manual syringe for 180 s simulating inhalations and exhalations at rest, light, moderate and vigorous activities (10, 60, 80 and 120 L/min, respectively). Statistical analysis showed that practically half of the air entering to the system is not filtered by the facemasks in all intensities (p < 0.001, ηp² = 0.971). They also showed that the hygienic facemasks filter more than 70% of the air, and their filtration does not depend on the simulated intensity, while the rest of the facemasks show an evidently different response, influenced by the amount of air mobilized. Therefore, the Real Bacterial Filtration Efficiency can be calculated as a modulation of the Bacterial Filtration Efficiencies that depends on the type of facemask. The real filtration capacity of the facemasks has been overestimated during last years since the filtration of the fabrics is not the real filtration when the facemask is worn.

Effects of Face Masks on the Multiple Dimensions and Neurophysiological Mechanisms of Exertional Dyspnea

INTRODUCTION

During the coronavirus disease 2019 pandemic, public health officials widely adopted the use of face masks (FM) to minimize infections. Despite consistent evidence that FMs increase dyspnea, no studies have examined the multidimensional components of dyspnea or their underlying physiological mechanisms.

METHODS

In a randomized crossover design, 16 healthy individuals ( n = 9 women, 25 ± 3 yr) completed incremental cycling tests over three visits, where visits 2 and 3 were randomized to either surgical FM or no mask control. Dyspnea intensity and unpleasantness were assessed throughout exercise (0-10 Borg scale), and the Multidimensional Dyspnea Profile was administered immediately after exercise. Crural diaphragmatic EMG and esophageal pressure were measured using a catheter to estimate neural respiratory drive and respiratory muscle effort, respectively.

RESULTS

Dyspnea unpleasantness was significantly greater with the FM at the highest equivalent submaximal work rate achieved by a given participant in both conditions (iso-work; 5.9 ± 1.7 vs 3.9 ± 2.9 Borg 0-10 units, P = 0.007) and at peak exercise (7.8 ± 2.1 vs 5.9 ± 3.4 Borg 0-10 units, P = 0.01) with no differences in dyspnea intensity ratings throughout exercise compared with control. There were significant increases in the sensory quality of "smothering/air hunger" ( P = 0.01) and the emotional response of "anxiousness" ( P = 0.04) in the FM condition. There were significant increases in diaphragmatic EMG and esophageal pressure at select submaximal work rates, but no differences in heart rate, pulse oximetry-derived arterial oxygen saturation, or breathing frequency throughout exercise with FMs compared with control. FMs significantly reduced peak work rate and exercise duration (both P = 0.02).

CONCLUSIONS

FMs negatively impact the affective domain of dyspnea and increase neural respiratory drive and respiratory muscle effort during exercise, although the impact on other cardiorespiratory responses are minimal.

Effects of Wearing a Mask During Exercise on Physiological and Psychological Outcomes in Healthy Individuals: A Systematic Review and Meta-Analysis

BACKGROUND

Wearing face masks in public is an effective strategy for preventing the spread of viruses; however, it may negatively affect exercise responses. Therefore, this review aimed to explore the effects of wearing different types of face masks during exercise on various physiological and psychological outcomes in healthy individuals.

METHODS

A literature search was conducted using relevant electronic databases, including Medline, PubMed, Embase, SPORTDiscus, Web of Science, and Cochrane Central Register of Controlled Trials on April 05, 2022. Studies examining the effect of mask wearing (surgical mask, cloth mask, and FFP2/N95 respirator) during exercise on various physiological and psychological parameters in apparently healthy individuals were included. For meta-analysis, a random effects model was used. Mean difference (MD) or standardized MD (SMD) with 95% confidence intervals (CI) were calculated to analyze the total effect and the effect in subgroups classified based on face mask and exercise types. The quality of included studies was examined using the revised Cochrane risk-of-bias tool.

RESULTS

Forty-five studies with 1264 participants (708 men) were included in the systematic review. Face masks had significant effects on gas exchange when worn during exercise; this included differences in oxygen uptake (SMD - 0.66, 95% CI - 0.87 to - 0.45), end-tidal partial pressure of oxygen (MD - 3.79 mmHg, 95% CI - 5.46 to - 2.12), carbon dioxide production (SMD - 0.77, 95% CI - 1.15 to - 0.39), and end-tidal partial pressure of carbon dioxide (MD 2.93 mmHg, 95% CI 2.01-3.86). While oxygen saturation (MD - 0.48%, 95% CI - 0.71 to - 0.26) decreased slightly, heart rate was not affected. Mask wearing led to higher degrees of rating of perceived exertion, dyspnea, fatigue, and thermal sensation. Moreover, a small effect on exercise performance was observed in individuals wearing FFP2/N95 respirators (SMD - 0.42, 95% CI - 0.76 to - 0.08) and total effect (SMD - 0.23, 95% CI - 0.41 to - 0.04).

CONCLUSION

Wearing face masks during exercise modestly affected both physiological and psychological parameters, including gas exchange, pulmonary function, and subjective discomfort in healthy individuals, although the overall effect on exercise performance appeared to be small. This review provides updated information on optimizing exercise recommendations for the public during the COVID-19 pandemic.

SYSTEMATIC REVIEW REGISTRATION NUMBER

This study was registered in the International Prospective Register of Systematic Review (PROSPERO) database (registration number: CRD42021287278).

The effects of cloth face masks on cardiorespiratory responses and VO2 during maximal incremental running protocol among apparently healthy men

We aimed to determine the effects of wearing a cloth face mask on cardiorespiratory response, peak oxygen uptake (Vo₂), respiratory muscle effort, and exercise tolerance during incremental exercise. The study had a randomized crossover design: 11 apparently healthy young men performed the Bruce protocol treadmill test in two conditions, wearing a cloth face mask (CFM) and without CFM (CON), in random order. Minute ventilation and oxygen uptake were measured using a mass spectrometry metabolic analyzer; cardiac output (CO) was measured using an impedance CO monitor; and mouth pressure (P_m) was measured and calculated as an integral P_m to assess respiratory muscle effort. Maximal minute ventilation was 13.4 ± 10.7% lower in the CFM condition than in the CON condition (P < 0.001). The peak Vo₂ (52.4 ± 5.6 and 55.0 ± 5.1 mL/kg/min in CFM and CON, respectively) and CO were not significantly different between the two conditions. However, the integral value of P_m was significantly higher (P = 0.02), and the running time to exhaustion was 2.6 ± 3.2% lower (P = 0.02) in the CFM condition than in the CON condition. Our results suggest that wearing a cloth face mask increased respiratory muscle effort and decreased ventilatory volume in healthy young men; however, Vo₂ remained unchanged. Exercise tolerance also decreased slightly.

Effects of Wearing FFP2 Masks on SARS-CoV-2 Infection Rates in Classrooms

In this retrospective cohort study involving 614 secondary school students, the likelihood of becoming infected with SARS-CoV-2 in schools with different focus (sports focus vs. general branch; the only difference in the sports focus school was that PE was allowed at all times without restrictions) and different prevailing restrictions were compared. A significantly higher likelihood of infection with SARS-CoV-2 was found in sports classes during the period with a strict FFP-2 mask requirement compared to general branch classes (for Delta from November 2021 to December 2021, and for Omicron from January 2022 to February 2022). The higher likelihood of infection was observed both during the Delta and the Omicron wave. After the relaxation of the mitigation measures, however, students in general branch classes showed a clear "catch-up" of infections, leading to a higher incidence of infections during this phase. By the end of the observation period (30 April 2022), only a small difference in cumulative SARS-CoV-2 infection rates (p = 0.037, φ = 0.09) was detected between classes with a sports focus and those without a sports focus. The results suggest that SARS-CoV-2 transmission can be reduced in school classes by mandatory FFP-2 mask use. In many cases, however, infection appears to be postponed rather than avoided.

Physiological Effects of Exercising at Different Intensities Wearing Surgical or Double-layer Cotton Facemasks Compared to Not Wearing a Mask

Since the beginning of the SARS-CoV-2 pandemic, the community use of facemasks has been widely recommended. However, their use during exercise has raised safety concerns. Thus, we compared the physiological differences between exercising wearing a surgical (SM) or a double-layer-cotton (DLC) facemask and not wearing a mask (NM). Sixteen volunteers underwent 4 bouts of cycling-based exercise, which consisted of two different intensities: light-to-moderate and moderate-to-high. Facemasks were used as follows: bout-1 and 4: NM; bout-2: SM or DLC and bout-3: DLC or SM. Ventilatory, metabolic, pulmonary gas exchange (PGE) and perceptual variables were collected. At both exercise intensities compared to NM, both facemasks induced similar ventilatory adaptations, increasing inspiratory time and tidal volume and decreasing breathing frequency. Effect sizes (ES) were larger for DLC than for SM. At moderate-to-high, both facemasks reduced the minute ventilation, whereas at light-to-moderate, it was only seen with DLC. End tidal and mixed CO₂ pressures, as well as the difference between them, increased with both facemasks. Again, ES was larger for DLC than SM. No relevant oxygen saturation drop was observed with both facemaks and exercise intensities. A small ES increament in VO₂ and VCO₂ were seen with both facemasks. Effort perception increased at moderate-to-high for both exercise intensities, buth larger EF were with DLC than SM . DLC increased facial temperature during both exercise intensities. In conclusion, ventilatory adjustments imposed during facemask exercise influenced PGE and metabolic and perceptual changes. Larger ES were mostly seen for DLC than SM.Novelty Bullets Facemasks affect the breathing pattern by changing the frequency and amplitude of pulmonary ventilation.The augmented ventilatory work increases VO2, VCO2, and RPE and promotes nonconcerning drops in SpO2 and CO2 retention.Increased inspiratory and expiratory pressure can account for the reduction in pulmonary physiological dead space.