Introduction: Training loads and heart rate variability (HRV) were monitored over 69 weeks in a swimming Olympic champion to assess if different types of HRV changes occurred during fatigue episodes. Methods: Weekly training volume (km) and training load (TL, a.u.) were calculated. Morning HRV tests were performed by recording R-R intervals at rest during 8 min supine (SU) and 7 min standing (ST). HRV variables analysed were: heart rate (HR), power (in ms2) of low (LF), high (HF) and (LF+HF) frequencies. Results: Over the period considered, training volume and TL amounted to 2408 km and 1075 a.u.. 55 HRV tests were completed, 10 took place in conditions of `fatigue` defined by the coach after training sessions.Three different sub-categories of fatigue were disclosed: type 1. F(HF-LF-)SU_ST (n=6) embeded a decrease inHF (-55%), LF( -23%) and an increase in HR (+21%) in SU, concomitant with a decrease in HF (-50%), LF(-50%) and an increase in HR (+16%) in ST; type 2. F(LFST) (n=2) featured a decrease in LF (-61%) and an increase in HR (+19%) in ST; type 3. F(HFSUHF+ST) embedded a decrease in HF (-72%) and an increase inHR (+10%) in SU, with an increase in HF (+65%) and a decrease in HR (-14%) in ST. Conclusion: In an elite swimmer, three different types of `fatigue` shifts in HRV patterns were sorted. Each type corresponded to specific changes in sympathovagal settings. To our knowledge, this study is the first one reporting a practical way of monitoring different types of fatigue apart from Nordic skiers.
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