Heart rate persons with coronary artery disease. The heart rate is rhythmically generated by the sinoatrial node. It is also influenced by central factors through sympathetic and parasympathetic nerves. Nervous influence over the heartrate is centralized within the two paired cardiovascular centres of the medulla oblongata. The cardioaccelerator regions stimulate activity via sympathetic stimulation of the cardioaccelerator nerves, and the cardioinhibitory centers decrease heart activity via parasympathetic stimulation as one component of the vagus nerve. During rest, both centers provide slight stimulation to the heart, contributing to autonomic tone. This is a similar concept to tone in skeletal muscles. Normally, vagal stimulation
Heart rate they generalized population-averages and usually focus on a person's age. It is well-established that there is a "poor relationship between maximal heart rate and age" and large standard deviations relative to predicted heart rates. ("see Limitations of Estimation Formulas"). A number of formulas are used to estimate HR Based on measurements of 3320 healthy men and women aged between 19 and 89, and including the potential modifying effect of gender, body composition, and physical activity, Nes "et al" found This relationship was found to hold substantially regardless of gender, physical activity status, maximal oxygen uptake, smoking, or body mass index.