Performing moderate to severe activity is safe and tolerable for healthy youth while wearing a cloth facemask.

OBJECTIVE: To investigate if a cloth facemask could affect physiological and perceptual responses to exercise at distinct exercise intensities in healthy young individuals. METHODS: Nine participants (sex, female/male: 6/3; age: 13±1 years; VO2peak: 44.5±5.5 mL/kg/min) underwent a progressive square-wave test at four intensities: (1) 80% of ventilatory anaerobic threshold (VAT), (2) VAT, and (3) 40% between VAT and [Formula: see text] wearing a triple-layered cloth facemask or not. Participants then completed a final stage to exhaustion at a running speed equivalent to the maximum achieved during the cardio-respiratory exercise test (Peak). Physiological, metabolic, and perceptual measures were measured. RESULTS: Mask did not affect spirometry (forced vital capacity, peak expiratory flow, forced expiratory volume; all p≥0.27), respiratory (inspiratory capacity, end-expiratory volume [EELV] to functional vital capacity ratio, EELV, respiratory frequency [Rf], tidal volume [VT], Rf/VT, end-tidal carbo dioxide pressure, ventilatory equivalent to carbon dioxide ratio; all p≥0.196), hemodynamic (heart rate, systolic and diastolic blood pressure; all p>0.41), ratings of perceived exertion (p = 0.04) or metabolic measures (lactate; p = 0.78) at rest or at any exercise intensity. CONCLUSIONS: This study shows that performing moderate to severe activity is safe and tolerable for healthy youth while wearing a cloth facemask. TRIAL REGISTRATION: ClinicalTrials.gov: NCT04887714.

A Cloth Facemask Causes No Major Respiratory or Cardiovascular Perturbations During Moderate to Heavy Exercise.

PURPOSE: Investigate whether a cloth facemask could affect physiological and perceptual responses to exercise at distinct exercise intensities in untrained individuals. METHODS: Healthy participants (n = 35; 17 men, age 30 [4] y, and 18 women, age 28 [5] y) underwent a progressive square wave test at 4 intensities: (1) 80% of ventilatory anaerobic threshold; (2) ventilatory anaerobic threshold; (3) respiratory compensation point; and (4) exercise peak (Peak) to exhaustion, 5-minute stages, with or without a triple-layered cloth facemask (Mask or No-Mask). Several physiological and perceptual measures were analyzed. RESULTS: Mask reduced inspiratory capacity at all exercise intensities (P < .0001). Mask reduced respiratory frequency (P = .001) at Peak (-8.3 breaths·min-1; 95% confidence interval [CI], -5.8 to -10.8), respiratory compensation point (-6.9 breaths·min-1; 95% CI, -4.6 to -9.2), and ventilatory anaerobic threshold (-6.5 breaths·min-1; 95% CI, -4.1 to -8.8), but not at Baseline or 80% of ventilatory anaerobic threshold. Mask reduced tidal volume (P < .0001) only at respiratory compensation point (-0.5 L; 95% CI, -0.3 to -0.6) and Peak (-0.8 L; 95% CI, -0.6 to -0.9). Shallow breathing index was increased with Mask only at Peak (11.3; 95% CI, 7.5 to 15.1). Mask did not change HR, lactate, ratings of perceived exertion, blood pressure, or oxygen saturation. CONCLUSIONS: A cloth facemask reduced time to exhaustion but had no major impact on cardiorespiratory parameters and had a slight but clinically meaningless impact on respiratory variables at higher intensities. Moderate to heavy activity is safe and tolerable for healthy individuals while wearing a cloth facemask. CLINICALTRIALS: gov: NCT04887714.

A cloth facemask increased ratings of perceived exertion and reduced affect, without affecting sprint or muscular performance.

We determined the effects of wearing a cloth facemask on exercise performance and subjective responses during training of track and field athletes. Track and field athletes (n = 10, sprinters and long jumpers) performed two training sessions with and without a three-layered antiviral cloth facemask. The training session simulated the specific demands of the sport, consisting of five 30-m sprints, interspersed with passive 4-min intervals. Countermovement jump performance was assessed pre- and post-sprints, and ratings of perceived exertion (RPE) and affect were collected throughout. There was no evidence of condition*time interactions for sprint time (P = 0.21) or acceleration (P = 0.47). There was weak evidence of a condition effect on RPE (P = 0.05), though no condition*time interaction (P = 0.35). There was moderate evidence of a condition*time interaction for affect (P = 0.02), with lower ratings following sprints 3, 4 and 5 when using the mask. These findings suggest that wearing a mask may negatively impact subjective feelings of training without necessarily harming sprint performance.

Extracellular pH, osmolarity, temperature and humidity could discourage SARS-CoV-2 cell docking and propagation via intercellular signaling pathways.

The COVID-19 pandemic and its virus variants continue to pose a serious and long-lasting threat worldwide. To combat the pandemic, the world's largest COVID-19 vaccination campaign is currently ongoing. As of July 19th 2021, 26.2% of the world population has received at least one dose of a COVID-19 vaccine (1.04 billion), and one billion has been fully vaccinated, with very high vaccination rates in countries like Israel, Malta, and the UEA. Conversely, only 1% of people in low-income countries have received at least one dose with examples of vaccination frequency as low as 0.07% in the Democratic Republic of Congo. It is thus of paramount importance that more research on alternate methods to counter cell infection and propagation is undertaken that could be implemented in low-income countries. Moreover, an adjunctive therapeutic intervention would help to avoid disease exacerbation in high-rate vaccinated countries too. Based on experimental biochemical evidence on viral cell fusion and propagation, herein we identify (i) extracellular pH (epH), (ii) temperature, and (iii) humidity and osmolarity as critical factors. These factors are here in discussed along with their implications on mucus thick layer, proteases, abundance of sialic acid, vascular permeability and exudate/edema. Heated, humidified air containing sodium bicarbonate has long been used in the treatment of certain diseases, and here we argue that warm inhalation of sodium bicarbonate might successfully target these endpoints. Although we highlight the molecular/cellular basis and the signalling pathways to support this intervention, we underscore the need for clinical investigations to encourage further research and clinical trials. In addition, we think that such an approach is also important in light of the high mutation rate of this virus originating from a rapid increase.