Relationship between very low frequency heart rate variability and interleukin-6 levels in healthy young individuals.

The autonomic nervous system regulates chronic inflammation, with heart rate variability (HRV) reflecting this regulation. We investigated the relationship between HRV and inflammatory markers (IL-6, hs-CRP) in 26 healthy young adults (19.9 ± 0.8 years). Participants underwent 24-hour heart rate monitoring, and HRV indices were derived from the median of 5-minute segments. Bayesian correlation analysis was employed to estimate relationships between natural log-transformed (Ln) parameters. LnIL-6 showed substantial positive associations with 24-hour and night-time LnVLF (Bayes factor = 18.61 and 3.24, respectively), with 95% credible intervals entirely above zero. The VLF component is a unique indicator of serum IL-6 in young adults.