[automatically translated] The heart rate (HR) is controlled by the autonomic nervous system. The sinoatrial (SA) node has its own frequency of spontaneous depolarization known as "natural frequency" which is the measured frequency in the absence of sympathetic or parasympathetic impulses as you can get with denervation or pharmacological block. In normal subjects the intrinsic rate is approximately 100 bpm, depending on sex and age and is influenced by exercise, hypoxia and temperature variations. The subjects trained for endurance sports have a lower intrinsic rate. The effects of the sympathetic and parasympathetic system predominantly affecting the intrinsic FC and determine the current FC as parasympathetic activation reduces the FC, while sympathetic activation increases FC. Moreover, the effect of a component is associated with an increase in the activity of its counterpart, a phenomenon that has been defined as "antagonism accentuated." Traditional analysis of the electrocardiogram (ECG), considers only the intervals between electrocardiographic QRS complex (RR intervals) shorter or longer neglecting the difference in RR intervals. The heart rate variability (HRV) is represented by differences in RR intervals and the resulting instantaneous changes of FC. It is a physiological index of these differences in response to factors such as location, movement, the breathing rhythm and emotional states. In this review we analyzed the methods of study, the normal range and the effects of different physiological conditions on HRV.
|Number of pages||10|
|Journal||RIVISTA DELLA FACOLTÀ DI SCIENZE MOTORIE DELL'UNIVERSITÀ DEGLI STUDI DI PALERMO|
|Publication status||Published - 2010|