OBJECTIVES: The purpose of this study was to determine whether the type of training in a young population differentiates heart rate variability parameters between athlete groups and sedentary subjects. METHODS: The effect of different types of physical training on heart rate variability was evaluated in 10 aerobic trained athletes, in 7 anaerobic trained athletes, in 7 rugby players (mixed type training) and in 10 sedentary control subjects. All groups were age matched (18-34 years). Electrocardiogram tracings were recorded digitally in the supine position and standing position. Measures of heart rate variability were obtained, from both time- and frequency analysis of 10 min resting heart rate. After these tests, blood pressure was measured using an automatic inflation cuff. RESULTS: Resting heart rate was lower in aerobic and mixed type athletes compared to controls. Only aerobic athletes had evidence of increased vagal activity in the time domain compared with control subjects (increased SDNN supine, increased rMSSD supine and standing and pNN50 standing). In the frequency domain, aerobic athletes presented with both higher low-frequency and high-frequency power in the standing position and low-frequency power in the supine position compared to controls. CONCLUSIONS: It can be concluded that heart rate variability is affected by chronic exercise, especially in endurance trained athletes. This infers that especially aerobic exercising can have beneficial effects on the cardiovascular risk profile.