Background: At the end of 2019, a hitherto unknown coronavirus was identified in Wuhan (China) it was called SARS CoV-2 and the disease caused by it was named COVID-19. With the increase in cases an unusual manifestation for this type of virus began to appear: anosmia and dysgeusia, of uncertain etiology, which it could be an autonomic alteration, more precisely in the baroreflex. In this context, it seems likely that subclinical manifestations of baroreflex involvement occur. The regulation of the baroreflex is carried out by the vegetative nervous system through the balance between sympathetic and parasympathetic activity. The objective of this study is to verify whether patients with COVID-19 present alteration of this mechanism by means of ECG Holter recording Material and methods: the study design was cross-sectional, observational, descriptive, prospective inclusion and the sampling was non-probabilistic of convenience. Patients were included if they had a confirmed diagnosis of COVID-19 admitted to the Internal Medicine Service of JB Iturraspe Hospital in Santa Fe city, Argentina, in the period from May 10 to July 20, 2021. An ECG Holter recording was performed at rest for 5 minutes, determining the variables of the frequency domain using Fourier transform analysis through Kubios. Data are presented for frequency measures of HRV: low-frequency power (LF), and high-frequency power (HF) and normalized unit LFnu, HFnu. Were excluded patients with a diagnosis of diabetes mellitus of more than 5 years of evolution, medicated with beta-blockers or with a history of irradiation in the neck Results: 68 patients were studied. 62% were men 38% were women. The mean age was 48.9 ± 13.3 years. The median systolic blood pressure (SBP) was 120 mmHg (95 to 170) and the diastolic blood pressure (DBP) 80 mmHg (60 -110). The heart rate was 76 ± 13 beats per minute and the respiratory rate was 24 (16 to 40). Anosmia was observed in 22% (n = 15) and dysgeusia in 19% (n = 13). The variables of the analysis in the frequency domain were: LF 135.8 ms2 (13.7 - 2861.7); HF, 89.04 ms2 (4.14-5234.4), LFnu 57.57 ± 22.39, HFnu 43.18 ± 22.64. LF / HF ratio 2.1 ms2 ± 2.09. 41.2% (n = 28) of the patients had a high LF / HF ratio (> 2). Discussion: The high and low frequency components known as HF (High Frequency) representing predominantly parasympathetic function, and LF (Low Frequency) which is both sympathetic and parasympathetic activity; can be obtained through the analysis in the frequency domain. The relationship between these two elements would thus represent the sympatho-vagal balance and is expressed as the LF / HF ratio. We observed that 41.2% of the studied patients showed elevated LF / HF ratio Conclusion: The 41.2% of the patients hospitalized with COVID-19 presented with an increase in the LF / HF ratio and this result could be interpreted as an alteration in autonomic function.