Physiological factors influencing heart rate variability

To assess the autonomic disturbancies in neurological disorders different methods of heart rate variability (HRV) measurement are recommended. Computer based measurements of HRV are easy to perform but difficult to interpret. Physiological influences on HRV must be controlled to get reproducible data. This paper describes factors know so far to be important for the interpretation of testing results such as age and respiration. Gender, caffeine or nicotine intake and pregnancy have a minor impact. The influence of training status and retest variability remains to be established.