As defined by the Mayo Clinic, the heart rate is the number of heartbeats per minute (bpm). It is based on the number of ventricle contractions located in the heart’s lower chambers. A heart rate also gives the pulse reading used as a vital for checking the body’s condition. The pulse is a sensation of pressure created by the force of blood moving through blood vessels because of the heart rate. Checking the pulse and its intervals of pressure gives an estimation of the heart rate. Normal heart rates are 60 to 100 bpm. The lower the number, the more efficient the heart is in its operation. Heart rates can be affected by activity, level of fitness, emotional condition and medicine.

The heart rate is controlled by the body’s system of electrical and chemical responses regulated by the nervous system. The sympathetic nervous system is a section of the nervous system that, in working with the parasympathetic nervous system, regulates automatic functions of the body including heart rate. The sympathetic and parasympathetic nervous systems can change how bodily functions are working during times of stress. In the fight-or-flight state, the human body undergoes changes including faster breathing, changes in pupil dilation and a faster heart rate. It is this reflex and response that can be triggered by sound, especially loud and sudden noises that trigger the nervous system to react. This reaction is a basic human body function designed to respond to danger (e.g., alerted by the sound of an animal’s growl.) This reaction speeds up the heart rate.

A type of sound therapy is used to positively affect the heart rate. By stimulating nerves within the ear, the parasympathetic system can be relaxed, causing a slowing of the heart rate and breathing. Some types of sound therapy also claim to affect the neurotransmission of pathways in the brain, causing calming of the circulatory and sensory systems.