Heart rate variability and exercise, is there a physiological basis?

Abstract

This work has two objectives: 1) to give a pedagogical view about the complexity of the mathematical treatment of heart rate variability and 2) to analyze whether the mathematical treatment of the RR signal (distance between two R waves shown in an electrocardiogram) has a physiological basis. We reviewed the physiological mechanisms that explain one of the basic phenomena for the analysis of heart rate variability: respiratory sinus arrhythmia. The elementary mathematical bases as well as the mathematical methods of assessing the variability are analyzed. Finally, we offer a critical review of the physiological significance of the frequency bands obtained by the various methodologies of the RR signal processing. It is not clear whether the mathematical methods of RR signal processing can be an assessment tool for vegetative function. Therefore, this variable must be interpreted with caution, especially in the context of physical exercise and training.