What affects your heart rate? Good question. There are many factors that affect your heart rate, like physical or emotional stress, medications, smoking, caffeine, and illness. A person's heart rate fluctuates throughout the day, and people generally do not notice, unless there is a significant change. Being overly tired or dehydrated can affect your heart rate. In this last instance, your heart rate would increase in an effort to meet your body's demands.
Breathing
For many people, there is a natural occurrence during respiration; the heart rate increases slightly during inspiration and slows down during expiration. This is called sinus arrhythmia and is benign.
Stress
Donna D. Ignatavicius, MS RN, and M. Linda Workman, Ph.D., authors of "Medical-Surgical Nursing: Critical Thinking for Collaborative Care," explain that part of the human response to physical, psychological and emotional stress is an increase in heart rate. Exercise, fear, pain and anxiety cause the release of hormones called catecholamines, which increase heart rate. This increases blood flow to skeletal muscles to provide more energy for self-defense, escape and physical exertion.
Vagal Stimulation
Vagal stimulation involves special sensors in the body that respond to blood pressure changes. Baroreceptors are found in the aortic arch and respond to changes in blood pressure. The act of bearing down, as when a person has a bowel movement or strains to move or lift something heavy, increases pressure in the body. The baroreceptors signal the heart to slow down its rate to counter the elevated pressure. When blood pressure is too low, baroreceptors respond by signaling the heart to increase its rate in an attempt to increase blood pressure.
Medications
Prescriptions, over-the-counter drugs, herbal supplements and illicit drugs all affect the heart rate. Stimulants, like caffeine, ephedrine and cocaine, increase heart rate. Beta-blockers, like atenolol and metoprolol, and anti-arrhythmic medications, like digitalis preparations, slow down the heart rate.
Illness
Barbara McLean, CCNP, and Janice Zimmerman, MD, authors of "Fundamental Critical Care Support," discuss how fever, anemia and thyroid disease can affect the heart rate. High fever increases metabolic demands on the body; the heart rate increases to meet oxygen requirements. A diseased thyroid may cause either an elevated or decreased heart rate. Anemia (low red blood count) causes an elevated heart rate, because there is not enough oxygen-rich blood circulating through the body. The heart rate increases in an attempt to bring oxygen to body tissues.
Smoking
Cigarette smoke diminishes the blood's ability to carry oxygen to tissues, and the nicotine causes vasoconstriction, or narrowing of blood vessels, further decreasing the blood flow to tissues and vital organs. The heart rate increases to counter this.
Arrhythmias
The Mayo Clinic explains that a damaged heart from a heart attack can lead to irregular heart rhythms, called arrhythmias. Arrhythmias can cause tachycardia (a heart rate that is too fast) or bradycardia (a heart rate that is too slow). To control the heart rate and rhythm, medications and, sometimes, a pacemaker are needed.
References
- "Medical-Surgical Nursing - Critical Thinking for Collaborative Care"; Donna D. Ignatavicius, MS RN, and M. Linda Workman, Ph.D.; 2006
- "Fundamental Critical Care Support (4th Edition.)"; B. McLean & J.L. Zimmerman; 2007
- Mayo Clinic: Heart Arrhythmias: Causes
Member Comments