Assessment of autonomic function indicators of heart rate variability aimed to assess cumulative fatigue

We determined subjective fatigue level among twenty healthy subjects by two questionnaires (CFSI and POMS) and classified them into very fatigued group (B-group) and scarcely fatigued group (G-group). Then we gave simple task to each group and assessed autonomic function indicators of HRV (CV-RR, LF,HF, and LF/HF). Moreover we performed same experiment among three subjects 8 or 9 times that was classified into very fatigued state (B-state) and scarcely fatigued state (G-state). As the result, B-group tended to indicate lower CV-RR and higher LF/HF than G-group, and when task was given, B-group had an individual difference in LF/HF although G-group indicated lower LFMF. Similarly, B-state tended to indicate higher LF/HF than G-state. The results showed when one was in a fatigue state, the parasympathetic activity was low level, and sympathetic activity was dominant, and the balance of sympathetic and parasympathetic activity became different from a scarcely fatigued state. These tendency indicated one became a tension state in the fatigue. As autonomic function indicators of HRV reflected fatigue level, assessment of the cumulative fatigue from physiological reaction could be possible.