Effects of Covid-19 on Autonomic Function Modulation in Young Adults: An Observational Prospective Case-Control Study

RESEARCH OBJECTIVES: To observe the effects of COVID-19 infection on ANS function over a follow-up period in young adults. DESIGN: Observational prospective case-control study. Subjects were evaluated at baseline and in a follow-up visit six weeks following the first shot of SARS-CoV-2 immunization. SETTING: Private Physical Therapy ambulatory. PARTICIPANTS: Male and female subjects aged 20-40 years with, a diagnosis of mild or moderate clinical COVID-19 with a positive PCR test and slight clinical symptoms, and who were not admitted to intensive care unit. Participants were recruited after a minimum of 15 and a maximum of 120 days of diagnosis (PCOV). An age-matched heathy control group (CG) that was negative for COVID-19 was also recruited. INTERVENTIONS: Autonomic nervous system function was measured through heart rate variability (HRV). Heart rate was recorded beat-to-beat to evaluate cardiac autonomic modulation. We used a cardio-frequency meter (Polar RS800CX). Participants were equipped with a chest strap and monitor and remained at rest for 25 minutes. MAIN OUTCOME MEASURES: Sympathetic and Parasympathetic indexes through HRV. RESULTS: 57 subjects were evaluated at baseline. After 19 exclusions, 38 subjects with complete data were included in the baseline analysis where 18 subjects were in CT and 20 in the PCOV group. Regarding sympathetic nervous system activity, there was no difference between baseline and follow-up moments within CT or PCOV groups (p>0.05). For intergroup analysis, we observed that PCOV group presents significant higher reductions in sympathetic activity over time when compared to CT demonstrated by HR (p=0.0088) and SNS index (p=0.0068). Observations of parasympathetic nervous system activity reveals a statistical increase between baseline and follow up in Mean RR (p=0.0312) and pNN50 (p=0.0312) for PCOV group. The intergroup analysis revealed that PCOV group presented a significant higher increase in parasympathetic activity overtime demonstrated by mean RR (-44.54±32.38 vs. 60.36±55.35; p= 0.0097) and PNS index (-0.32±0.20 vs. 0.54 ± 0.35; p= 0.0091) when compared to CT. CONCLUSIONS: Sympathetic activity decreased in PCOV after infection and over the follow up period. AUTHOR(S) DISCLOSURES: Authors declare no conflicts.