Decreased heart rate variability is associated with higher levels of inflammation in middle-aged men

Area of Science:

• Cardiology
• Autonomic Nervous System Function
• Inflammation and Disease

Background:

• Traditional coronary artery disease (CAD) risk factors correlate with altered autonomic function.
• Inflammation may bridge the gap between risk factors, autonomic dysfunction, and CAD.
• This study investigates the relationship between heart rate variability (HRV) and inflammatory markers C-reactive protein (CRP) and interleukin-6 (IL-6).

Purpose of the Study:

• To examine the association between HRV, a measure of autonomic function, and inflammation (CRP and IL-6).
• To determine if traditional CAD risk factors influence this association.

Main Methods:

• 264 middle-aged male twins without symptomatic CAD were studied.
• Ambulatory electrocardiogram monitoring was used to calculate HRV parameters via power spectral analysis.
• Inflammatory markers (CRP, IL-6) and various CAD risk factors (age, smoking, BMI, lipids, hypertension, diabetes, depression, physical activity) were assessed.

Main Results:

• Physical activity, BMI, HDL cholesterol, smoking, depression, and hypertension were associated with higher CRP and IL-6 levels and lower HRV.
• A dose-response inverse relationship was observed between most HRV parameters and CRP/IL-6.
• Ultra-low and very-low frequency HRV remained significant predictors of CRP even after adjusting for multiple CAD risk factors.

Conclusions:

• C-reactive protein (CRP) is significantly associated with decreased heart rate variability (HRV).
• This association remains robust after controlling for established coronary artery disease (CAD) risk factors.
• Autonomic dysregulation may promote CAD development through inflammation.