Return to play after health complications associated with infectious mononucleosis guided on autonomic nervous system activity in elite athlete: A case study [Rekonvalescence po infek ní mononukleóze ízená na základě aktivity autonomního nervového systému u vrcholového sportovce: Kazuistika]

BACKGROUND: Infectious mononucleosis (IM) is an acute serious illness which requires among other things an interruption of training. The return to play for athletes after IM is complicated and a long-term process which could result in the relapse of health complications linked fundamentally with the illness. OBJECTIVE: The aim of this study was to design a convalescence program which leads to an improvement in physical fitness and provides a safe return to play without relapse of health complications for an elite athlete who suffered from IM. METHODS: The convalescence program lasted almost 3 months. Training load was optimized based on autonomic nervous system (ANS) activity which was assessed by spectral analysis (SA) of heart rate variability (HRV). There were evaluated an individual spectral variables: very low frequency power (PVLF) (0.02-0.05 Hz); low frequency power (PLF) (0.05-0.15 Hz), high frequency power (PHF) (0.15-0.50 Hz), total power (PT) (0.02-0.50 Hz), ratio PVLF/PHF and PLF/PHF; heart rate (HR), and age-dependent complex index of SA HRV: index of vagal activity, sympathovagal balance, and total score. Further, perceived exertion during exercise and morning fatigue was assessed. Repeated biochemical analysis was focused on the selected transaminase level. RESULTS: Among recovery periods, an increase in mean of PT was accompanied by elevation of PVLF/PHF and PLF/PHF. No significant differences in mean values of any complex index of SA HRV among periods were found. A decline in HR was identified during measurements in lying, but mostly in supine. A significant elevation of perceived exertion during exercise occurred between periods. The morning fatigue culminated during the last period. No relationship between subjective feeling of fatigue and complex index of SA HRV was found. CONCLUSIONS: A convalescence strategy based on assessment of ANS activity brought an improvement in physical fitness, in spite of borderline or mild elevated transaminase level. We suggest that a combination of both non-invasive SA HRV and periodic assessment of biochemical indicators of liver state seems to be a promising strategy for determination of safe application of training load during convalescence after IM. [VYCHODISKA: Infek ní mononukleóza (InM) je záva nym onemocněním vyvolané Epstein-Barr virem, které vy aduje okam ité p eru ení tréninku. CíLE: Hlavním cílem na í práce bylo vytvo it optimální rekondi ní program pro vrcholového sportovce po recidivě InM, ktery povede k jeho bezpe nému návratu do vrcholového sportu. METODIKA: ízená rekonvalescence trvala