Lower heart rate variability is associated with higher serum high-sensitivity C-reactive protein concentration in healthy individuals aged 46 years or more

Background To test the hypothesis of an association between cardiac autonomic activity evaluated by heart rate variability and systemic inflammatory markers such as C-reactive protein, we studied the correlation of the indices of heart rate variability relative to serum high-sensitivity C-reactive protein (hs-CRP) in a healthy Brazilian population. Methods Four hundred twenty-one healthy individuals aged 15–82 years (mean 40.4 years), 184 men (43.7%) and 237 women (56.3%) were enrolled between July 1998 and July 2001. The relationship between the log-transformed indices of the heart rate variability and the serum concentration of hs-CRP were analyzed stratified by age tertile using the Spearman correlation coefficient and multiple linear regression. Results The log standard deviation of all normal sinus RR intervals over 24 h (SDNN) (r = − 0.801; p = 0.024) was independently correlated with log hs-CRP in the individuals with age in the oldest tertile (≥ 46 years). In addition, the body mass index (BMI) was independently correlated with hs-CRP in all of the age groups. Conclusions In the healthy subjects aged 46 years or more the lower heart rate variability correlated with higher concentration of hs-CRP.