Heart rate variability is dependent on the level of heart rate

Department of Pharmacological Sciences, Medical School, University of Tampere, Tampere, Finland (Nieminen)

Department of Clinical Physiology, Tampere University Hospital and Medical School, University of Tampere, Tampere, Finland (Kähönen)(Kööbi)

Heart Center, Department of Cardiology, Pirkanmaa Hospital District, Pirkanmaa, Finland (Nikus)

Ragnar Granit Institute, Tampere University of Technology, Tampere, Finland(Viik)