Physiological impact of the facial mask at rest (2): Modification of Cardiac Variability (HRV) in young athletes

During the imperative mandate of mask-wearing during the COVID-19 pandemic, our study aimed to elucidate the physiological repercussions stemming from hypoxia and hypercapnia induced by facemasks during periods of rest. Specifically, we investigated the influence of facemasks on heart rate variability (HRV) within a cohort of young athletes. Experimental study in which 56 competitive adolescent athletes (55 % female) were evaluated. The heart rate data was recorded during 8-min, in meditative rest while seated. We conducted a comprehensive analysis of heart rate variability, examining both a 4-min segment and a 100-beat window. Comparisons were made between data recorded when subjects wore facemasks and when they breathed freely without masks. Data analysis was performed utilizing the Polar ProTrainer 5 software. The results showed relevant statistical differences at the level of cardiac variability (HRV): a) Heart Rate (mask: 70.5 ± 11.3 bpm vs no mask: 71.4 ± 12 bpm; p < 0.043. b) RMSSD (Mask: 56.8 ± 41.1 ms vs no mask: 48.9 ± 30.8 ms p < 0.002). c) RMSSD only 100 beats (mask: 58.1 ± 42.0 ms vs no mask: 46.7 ± 28.4 ms; p < 0.0001). Upon removing the facemask while maintaining meditative rest, 86 % of the subjects exhibited a distinct sympathetic response during the subsequent 5-min period. Notably, in 13 % of participants, this sympathetic response persisted across both phases of the study. Furthermore, the analysis of Ultra-Short-Term Cardiac Variability based on 100 beats accentuated the significance of the observed differences.