BACKGROUND: Obesity has been shown to affect heart rate variability (HRV). Adipokines (hormone-like peptides secreted by adipose tissue) display several bioactivities and have an impact on the cardiovascular system. The aim of the study was to evaluate the impact of obesity (BMI > or = 30) and adipokines (leptin, adiponectin and resistin) on HRV. METHODS: In 43 obese and 38 non-obese males with acute myocardial infarction, plasma adipokines were determined. 24-hour Holter ECG with time and frequency domain HRV analysis was performed. RESULTS: Anthropometric measurements, leptin and resistin were significantly higher and adiponectin was lower in the obese than in the non-obese group. SDNN, SDANN, SDNN-i, rMSSD, p-NN50 and HF were reduced in obese patients, whereas LF/HF was higher. Waist circumference was a better correlate of HRV parameters than body mass index. Several associations between HRV parameters and adipokines were observed: between SDNN and leptin (r = -0.32; p < 0.001) and resistin (r = -0.26; p < 0.05); SDANN and leptin (r = -0.26; p < 0.05) and resistin (r = -0.29; p < 0.001); SDNN-i and resistin (r = -0.40; p < 0.001); LF and leptin (r = 0.22; p < 0.05); HF and resistin (r = -0.22; p < 0.05); LF/HF and leptin (r = 0.46; p < 0.001) and resistin (r = 0.44; p < 0.001). CONCLUSIONS: Obesity is related to sympathovagal imbalance characterized by depressed parasympathetic tone and increased sympathetic activity. The relation between blood leptin and resistin concentration to the HRV parameters may indicate a possible link between adipokines and disturbances of the autonomic nervous system.