Influence Of Physical Activity On Autonomic Function After Mild-to-moderate Covid-19 Infection In Young Adults

PURPOSE: To analyze the influence of physical activity (PA) on autonomic function after mild-to-moderate SARS-CoV-2 (COVID-19) infection in young adults. METHODS: Participants aged 20-40 years after mild or moderate COVID-19 with a previous positive PCR test and not admitted to intensive care unit (PCOV) were included in this study. subjects were recruited after 15 to 180 days of diagnosis by positive PCR test. An age-matched healthy control group (CT) that was negative for COVID-19 was also recruited. After a minimum of 6 weeks from the second shot of COVID-19 vaccine subjects were again recruited to follow up evaluations. Evaluations included heart rate variability (HRV) analysis, measured using a cardio-frequency meter. Subjects were equipped with a chest strap and monitor, and instructed to breathe naturally for 25 minutes. PA was measured using a triaxial accelerometer worn above the waist for seven consecutive days during waking hours. For intergroup comparisons between the PCOV and CT, an unpaired t-test or Mann-Whitney U-test was performed depending on data distribution. Analysis of covariance (ANCOVA) was used to observe the influence of PA on the HRV indexes. Additionally, a Pearson r or Spearman correlational analysis was performed to better illustate the influence of PA on HRV changes. RESULTS: PCOV presented significant reductions in sympathetic nervous system (SNS) activity over time when compared to CT demonstrated by mean heart rate (HR) (p = 0.0088) and SNS index (p = 0.0068). PCOV also presented with an increase in parasympathetic nervous system (PNS) activity over time demonstrated by mean RR (p = 0.0097) and PNS index (p = 0.0091) when compared to CT. No group or moment differences were observed in PA (p > 0.05). ANCOVA, including PA in the multivariable regression analysis model, portrayed significant group differences in mean HR (p = 0.014), SNS index (p = 0.015), mean RR (p = 0.012), and PNS index (p = 0.013) were maintained. No relationships were observed during correlational analysis (p > 0.05). CONCLUSIONS: Young adults infected with mild-to-moderate COVID-19 improved ANS function over a 5-month period. Significant findings were maintained during ANCOVA, while no correlational relationships were identified between PA and HRV indicating PA did not influence changes in HRV.