Does overtraining affect heart rate variability during sleep and after awakening in athletes compared to controls?
Overtrained athletes exhibit slightly diminished parasympathetic cardiac modulation after awakening, suggesting altered autonomic responses to physiological challenges.
The present findings suggest that in OA, cardiac autonomic modulation is at the level of control athletes during sleep, but the parasympathetic cardiac modulation is slightly diminished after awakening. Further investigations should concentrate on autonomic responses to different challenges, such as awakening in the present study.
Hynynen et al. (Wed,) studied this question.