Why should we monitor vagal control of the heart?

In health, cardiac vagal tone signifies cardiac reserve, or the stamina of the cardiovascular system. As cardiovascular stamina increases during training in athletes, the level of cardiac vagal tone also rises in response. It is an advantage for an athlete to monitor the building of his or her cardiovascular stamina during training and the decline of the stamina while not in training by monitoring the level of the cardiac vagal tone.There are two main reasons for monitoring the vagal control of the Heart in disease. To assess the function of the brain where the nervous signal originate from, and to assess cardiovascular health.Lack of vagal control of the heart has been associated with sudden death in diseases such as diabetes mellitus and ischaemic heart disease.Monitoring the level of cardiac vagal tone is important in such diseases. In neurology, cardiac vagal tone indicates the status of the autonomic nervous system, the nerves responsible for most of the automatic functions of the body such as the regulation of the blood pressure, heart rate and body temperature.