Effects of a competitive season on autonomic heart rate modulation in field soccer athletes

The physical demands of soccer combined with the rigor of the competitive season may have a substantial impact on autonomic modulation in field soccer athletes. The number of sudden death cases associated with soccer may be related to the physical training required to maintain performance and fitness, minimal time for recovery, and recurrent game participation. It is possible to identify individuals at risk of cardiovascular events by measuring heart rate variability (HRV), which is an indirect method for assessing autonomic activity. Therefore, the objective of this study was to analyze HRV before and after a period of field soccer competition. We evaluated 17 healthy male professional field soccer athletes and 12 untrained controls. The HRV was analyzed during supine rest before and after a period of field soccer competition. The following parameters were evaluated: interval R wave variation (RR), standard deviation of normal–normal intervals (SDNN), Root-mean-square successive difference (RMSSD), low frequency component (LF), high-frequency component (HF) and sympathovagal balance (LF/HF). Results indicated that the RR (p<.05, ES: 2.77), SDNN (p<.05, ES: 1.70), LF (p<.05, ES: 1.86), HF p<.05, ES: 0.89) and LF/HF p<.05, ES: 0.89) all decreased after the competition in the professional athletes with no change observed in the control group. In conclusion, the data suggest that a soccer competition negatively influences the autonomic regulation of heart rate.