AUTONOMIC NERVOUS SYSTEM ACTIVITY ASSESSMENT IN RECREATIONAL HALF MARATHON RUNNERS

BACKGROUND: Spectral analysis (SA) of heart rate variability (HRV) is considered to be a non invasive method for the quantification of autonomic cardiac activity in relationship to the sinoatrial node. It is well known that auto nomic regulation is affected by various stress factors such as anxiety and/or physical activity. OBJECTIVE: The aim of the present study was to evaluate the effect of pre -competitive anxiety on the autonomic nervous system (ANS) activity and, further, to monitor the time course of ANS recovery as well as perceived fatigue during 24 hours of a post -half marathon period in amateur runners. METHODS: The SA HRV method was used for the evaluation of autonomic cardiac regulation. ANS activity was assessed one week before a competition and on the day of the competition. During the post -competition period ANS activity was measured at the 1st, the 12th, and the 24th hour. ANS activity was represented by the standard spectral parameters and complex indexes of SA HRV. Precompetition anxiety was evaluated by means of a modified Likert 10 point scale. The competitors' subjective feelings of fatigue were scored on a 6 point scale. RESULTS: Perception of anxiety was significantly higher on the day of the competition than one week before the competition. The significant decrease in the complex index of sympathovagal balance on day of the competition implies l for and testifies to an increase in sympathetic activity. No significant differences between any selected HRV variables at the 12th hour as well as at the 24th hour of recovery compared to both pre -competition levels were found. Perceived fatigue remained significantly elevated up to the 24th hour of recovery. CONCLUSION: Our study shows that elevated pre -competitive anxiety induced sympathetic predominance in auto nomic regulation particularly during the period of orthostatic stimulation. ANS activity returned to its pre -competition level during the 12th hour after the finish of the competition. It is evident that the causes of soreness or fatigue do not markedly affect ANS activity during a later phase of recovery.