Emotions, such as fear, can greatly affect the heart rate, causing it to speed up considerably. The autonomic nervous system responds to fear and releases chemicals that cause the heart to increase in rate.
Resting Heart Rate
A normal resting heart rate is between 60 and 100 beats per minute. This may vary based on age, gender and the size of a person.
Autonomic Nervous System
The autonomic nervous system is responsible for the automatic responses the body makes, such as increasing digestive enzymes after eating and breathing more quickly while running.
Two Parts of the Autonomic Nervous System
The autonomic nervous system has two branches: the sympathetic and the parasympathetic. In most instances, the stimulation of the sympathetic branch has one effect on the body; the parasympathetic, the opposite effect.
FIght or Flight System
The sympathetic nervous system is usually activated when the body is stressed, or a person feels threatened. It reacts to the threat by readying the body to fight or flee by releasing chemicals, such as adrenaline. This causes the heartbeat to race, the pupils of the eyes to dilate and breathing to become quicker.
Parasympathetic
Once the threat has passed, the parasympathetic branch is activated and it responds by calming the body down. This allows the heart rate to return to a slower, normal rate.
Stress and Heart Rate
The sympathetic nervous system reacts during stressful times. Being constantly under stress can take a toll on the body, causing illness. Stress relief is key to good health.
Tags: nervous system, autonomic nervous, Heart Rate, heart rate, nervous system