In elite athletes integrated stress assessment may be of paramount importance for individual titration of optimal training or early recognition of incipient "overtraining". In these conditions the neurovegetative and neuro-humoral systems play a crucial role. However, to date a reliable tool for assessing stress induced changes in autonomic and neuro-hormonal control in athletes is lacking. We sought to determine whether combined, non invasive, evaluation of neural control of sinoatrial node along with endocrine and immune systems functioning might help detecting the influence of a stressful condition in elite athletes. Method: 7 top-level pentathletes were studied on a regular training day (Control) and on a trial day for race selection (Stress). In both experimental days subjects were studied in the morning after an overnight fasting, and at the end of the day. Salivary samples were used to determine free cortisol levels and cytokines concentration. ECG was recorded by a chest lead in the supine position by telemetry (HP system), for autonomic evaluation by autoregressive power spectral analysis of RR interval variability. Results: At control, RR interval values (mean, 1191±49 msec), variance (4172±1055msec2) and spectral distribution (LF/HF 1.0±0.2) were within normalits; free cortisol was higher in the morning than in the afternoon (3.6±0.4 viz 1.4±0.2 ng/mL, p<0.002). Conversely, in the stress day, cortisol was higher (p<0.02) both in the morning and in the afternoon (7.7±1.1 and 9.6±2.0 ng/mL) in comparison with control, thus suggesting an important involvement of the hypothalamic-pituitary-adrenal (HPA) axis. Conclusions: These results, although limited to a small data set, suggest that combined evaluation of autonomic and neuro-endocrine system performance are effective in evaluating the impact of stress on major control mechanisms in elite athletes.
© Copyright 1999 5th IOC World Congress on Sport Sciences with the Annual Conference of Science and Medicine in Sport 1999. Alle Rechte vorbehalten.