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

INTRODUCTION: During the Coronavirus disease (COVID-19) 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 cross-over design, sixteen healthy individuals (n = 9 females, 25 ± 3 y) completed incremental cycling tests over three visits, where visits 2 & 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 following exercise. Crural diaphragmatic electromyography (EMGdi) and esophageal pressure (Peso) 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 to 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 EMGdi 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 to control. FM 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.

Cardiorespiratory physiology, exertional symptoms, and psychological burden in post-COVID-19 fatigue.

Fatigue is a common, debilitating, and poorly understood symptom post-COVID-19. We sought to better characterize differences in those with and without post-COVID-19 fatigue using cardiopulmonary exercise testing. Despite elevated dyspnoea intensity ratings, V̇O2peak (ml/kg/min) was the only significant difference in the physiological responses to exercise (19.9 ± 7.1 fatigue vs. 24.4 ± 6.7 ml/kg/min non-fatigue, p = 0.04). Consistent with previous findings, we also observed a higher psychological burden in those with fatigue in the context of similar resting cardiopulmonary function. Our findings suggest that lower cardiorespiratory fitness and/or psychological factors may contribute to post-COVID-19 fatigue symptomology. Further research is needed for rehabilitation and symptom management following SARS-CoV-2 infection.

Incorporating remote patient monitoring in virtual pulmonary rehabilitation programs.

Most pulmonary rehabilitation (PR) programs have had to adapt due to the COVID-19 pandemic and associated restrictions. Current alternative home-based programs have limitations and require modification. In this paper, we outline a novel method to monitor home-based PR programs, which has the potential to improve PR safety and efficacy. This new method is based on a remote patient monitoring (RPM) system with connected smart devices that enables the Respiratory Therapist (RT) to have real-time access to patient data including heart rate and peripheral oxygen saturation during exercise. The RPM system also monitors daily physical activity, sedentary time, sleep quality, rescue inhaler use, and maintenance inhaler adherence, among other variables, which has the added advantage of predicting patterns consistent with symptoms that may require medical intervention. To increase privacy, data are anonymized at all levels and only the RT has access to patient information. RPM systems have the potential to give practitioners a holistic view of the participants' health status to better evaluate them during the entire PR program and to improve self-management. As this is not a formal research study, we cannot make definitive conclusions about the efficacy of the system, and further research is needed to examine safety and to compare our approach to other ways of conducting PR.

Pulmonary function and functional capacity in COVID-19 survivors with persistent dyspnoea.

The purpose of this study was to examine the physiological mechanisms of persistent dyspnoea in COVID-19 survivors. Non-critical patients (n = 186) with varying degrees of COVID-19 severity reported persistent symptoms using a standardized questionnaire and underwent pulmonary function and 6-minute walk testing between 30 and 90 days following the onset of acute COVID-19 symptoms. Patients were divided into those with (n = 70) and without (n = 116) persistent dyspnoea. Patients with persistent dyspnoea had significantly lower FVC (p = 0.03), FEV1 (p = 0.04), DLCO (p = 0.01), 6-minute walk distance (% predicted, p = 0.03), and end-exercise oxygen saturation (p < 0.001), and higher Borg 0-10 ratings of dyspnoea and fatigue (both p < 0.001) compared to patients without persistent dyspnoea. We have shown that dyspnoea is a common persistent symptom across varying degrees of initial COVID-19 severity. Patients with persistent dyspnoea had greater restriction on spirometry, lower DLCO, reduced functional capacity, and increased exertional desaturation and symptoms. This suggests that there is a true physiological mechanism that may explain persistent dyspnoea after COVID-19.

Face Masks and the Cardiorespiratory Response to Physical Activity in Health and Disease.

To minimize transmission of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), the novel coronavirus responsible for coronavirus disease (COVID-19), the U.S. Centers for Disease Control and Prevention and the World Health Organization recommend wearing face masks in public. Some have expressed concern that these may affect the cardiopulmonary system by increasing the work of breathing, altering pulmonary gas exchange and increasing dyspnea, especially during physical activity. These concerns have been derived largely from studies evaluating devices intentionally designed to severely affect respiratory mechanics and gas exchange. We review the literature on the effects of various face masks and respirators on the respiratory system during physical activity using data from several models: cloth face coverings and surgical masks, N95 respirators, industrial respirators, and applied highly resistive or high-dead space respiratory loads. Overall, the available data suggest that although dyspnea may be increased and alter perceived effort with activity, the effects on work of breathing, blood gases, and other physiological parameters imposed by face masks during physical activity are small, often too small to be detected, even during very heavy exercise. There is no current evidence to support sex-based or age-based differences in the physiological responses to exercise while wearing a face mask. Although the available data suggest that negative effects of using cloth or surgical face masks during physical activity in healthy individuals are negligible and unlikely to impact exercise tolerance significantly, for some individuals with severe cardiopulmonary disease, any added resistance and/or minor changes in blood gases may evoke considerably more dyspnea and, thus, affect exercise capacity.