Induced Relaxation Enhances the Cardiorespiratory Dynamics in COVID-19 Survivors

Author: Alejandra Margarita Sánchez-Solís1, Viridiana Peláez-Hernández2, Laura Mercedes Santiago-Fuentes1,3, Guadalupe Lizzbett Luna-Rodríguez2, José Javier Reyes-Lagos1, Arturo Orea-Tejeda2
Affiliation: <sup>1</sup> School of Medicine, Universidad Autónoma del Estado de México (UAEMéx), Toluca de Lerdo 50180, Mexico. <sup>2</sup> Cardiology Service, Instituto Nacional de Enfermedades Respiratorias Ismael Cosío Villegas (INER), Mexico City 14080, Mexico. <sup>3</sup> Health Sciences Department, Universidad Autónoma Metropolitana Unidad Iztapalapa (UAM-I), Mexico City 09340, Mexico.
Conference/Journal: Entropy (Basel)
Date published: 2023 May 30
Other: Volume ID: 25 , Issue ID: 6 , Pages: 874 , Special Notes: doi: 10.3390/e25060874. , Word Count: 204

Most COVID-19 survivors report experiencing at least one persistent symptom after recovery, including sympathovagal imbalance. Relaxation techniques based on slow-paced breathing have proven to be beneficial for cardiovascular and respiratory dynamics in healthy subjects and patients with various diseases. Therefore, the present study aimed to explore the cardiorespiratory dynamics by linear and nonlinear analysis of photoplethysmographic and respiratory time series on COVID-19 survivors under a psychophysiological assessment that includes slow-paced breathing. We analyzed photoplethysmographic and respiratory signals of 49 COVID-19 survivors to assess breathing rate variability (BRV), pulse rate variability (PRV), and pulse-respiration quotient (PRQ) during a psychophysiological assessment. Additionally, a comorbidity-based analysis was conducted to evaluate group changes. Our results indicate that all BRV indices significantly differed when performing slow-paced breathing. Nonlinear parameters of PRV were more appropriate for identifying changes in breathing patterns than linear indices. Furthermore, the mean and standard deviation of PRQ exhibited a significant increase while sample and fuzzy entropies decreased during diaphragmatic breathing. Thus, our findings suggest that slow-paced breathing may improve the cardiorespiratory dynamics of COVID-19 survivors in the short term by enhancing cardiorespiratory coupling via increased vagal activity.

Keywords: breathing and relaxation exercises; cardiorespiratory coupling; diaphragmatic breathing; post-COVID-19 syndrome; pulse–respiration quotient; slow breathing.

PMID: 37372218 DOI: 10.3390/e25060874