ANATOMY

Detailed explanation-1: -The sympathetic nervous system (SNS) releases the hormones (catecholamines-epinephrine and norepinephrine) to accelerate the heart rate.

Detailed explanation-2: -The principal functions of the heart are regulated by the sympathetic and parasympathetic divisions of the autonomic nervous system. In general, the sympathetic nerves to the heart are facilitatory, whereas the parasympathetic (vagus) nerves are inhibitory.

Detailed explanation-3: -Exercise stimulates the sympathetic nervous system and will induce an integrated response from the body; This response works to maintain an appropriate level of homeostasis for the increased demand in physical, metabolic, respiratory, and cardiovascular efforts.

Detailed explanation-4: -Heart rate is controlled by the activity of the autonomic nervous system: the sympathetic and parasympathetic nervous systems increase and suppress heart rate, respectively. To evaluate the activity of the autonomic nervous system, it is possible to determine heart rate variability using electrocardiography (ECG).

Detailed explanation-5: -Once exercise begins, the sympathetic nervous system is activated and the heart rate rises quickly. Heart rate also rises by simply thinking about exercise, which is referred to as anticipatory heart rate response. The parasympathetic division helps to slow down heart rate and respiration.