Effects of Covid-19 on Heart Rate Variability (HRV)

Covid-19 has been responsible for over 7.1 million deaths and 776 million infections globally since 2019. The long-term effects, including those related to the vaccinations, are still being studied. Previous research has used heart rate variability (HRV) to evaluate cardiac damage in severely affected Covid-19 patients, but its predictability in those with subacute cardiac conditions is unclear. We hypothesize that there is a correlation between HRV and exposure to Covid-19 and/or the vaccines used. HRV is a noninvasive method to assess cardiac health by measuring the time variation between heartbeats. The greater the variability, the better the cardiac health. This study utilized surveys and HRV data derived from electrocardiograms to investigate differences in HRV based on Covid-19 infection and vaccination history. T-tests indicated several significant findings: females exhibited higher variability (SD Rate) than males (p=0.031); individuals never infected with Covid-19 had a higher HRV (SDRR) compared to those infected two or more times (p=0.030); those receiving one or two Covid-19 vaccines had a higher HRV (avg RR) than those vaccinated three times or more (p=0.002); individuals receiving Pfizer for all doses showed a higher HRV (avg RR; median RR) compared to others (p=0.044; p=0.039); and individuals exercising two or fewer days a week had higher a HRV (SD Rate) than those exercising more frequently (p=0.002). The hypothesis that increased exposure to Covid-19 antigens—through infection or vaccination—correlates with decreased HRV is supported by these results. This finding suggests that increased exposure may worsen heart rate variability. Future research may indicate that using HRV has the potential to be a screening tool for identifying cardiac issues related to Covid-19 in the general population. Approved by Elon IRB 23-2912. Funded by the Undergraduate Research Program (URP) and the Department of Biology at Elon University. This abstract was presented at the American Physiology Summit 2025 and is only available in HTML format. There is no downloadable file or PDF version. The Physiology editorial board was not involved in the peer review process.