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Stress, as defined by the National Institute of Mental Health (NIMH), is the brain's
response to any demand; change. We mostly use the word today to describe the level of tension
we feel is placed on our minds and souls by the demands of our jobs, relationships, and
responsibilities in life (stressors). Cited by the World Health Organization (WHO) as “a global
epidemic”, stress, seems to know no age, race, gender, religion, nationality, or socioeconomic
class, thus giving it the title as “the equal opportunity destroyer” (Seaward, 2006). It has this title
because longtime stress can cause physiological responses and adaptations which can have
detrimental and even sometimes deadly affects on an individual. It can affect many of the body’s
systems including the respiratory, gastrointestinal, cardiovascular, endocrine, dermatological,
immune, and muscular skeletal and contribute to multiple health problems. Some symptoms may
be less severe such as diarrhea, nausea, indigestion, etc. and some may be much more severe
such as asthma and heart disease (Engs, 1987). For the purpose of this report however, I will
solely focus on the affects stress can have on the cardiovascular system.
The cardiovascular system, sometimes called the blood-vascular or the circulatory
system, consists of the heart, a closed system of vessels, and blood contained in the circulatory
system. Blood within the circulatory system, which consists of red blood cells (collect oxygen
from lungs and deliver to all parts of the body and carry waste products to the kidneys to be
removed from the body), white blood cells (help the body fight infection), platelets (help blood
clots form to stop bleeding when necessary), and plasma (liquid part of the blood consisting
mostly of diluted water), is pumped by the heart around the system of vessels, which consist of
the arteries (carry blood away from the heart), veins (carry blood to the heart), and capillaries
(tiny blood vessels that connect the arteries and veins), as it passes repeatedly through the
various circulations of the body (National Cancer Institute). The heart consists of four chambers,
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two upper, smaller chambers called the right and left atria, and two lower, larger chambers called
the right and left ventricles (Physiologyinfo.org). It is very important that your blood moves in
only one direction for proper flow. Valves between the chambers prevent blood from going
backwards. The cardiovascular system plays a vital role in maintaining homeostasis, which is
defined by Encyclopedia Britannica as any self-regulating process by which biological systems
tend to maintain stability while adjusting to conditions that are optimal for survival, by
continuous and controlled movement of blood through the thousands of miles of capillaries that
fill every tissue and reach every cell in the body (National Cancer Institute). When chronic
stressors are present the body is constantly aroused for danger therefore causing detrimental
effects on the cardiovascular system.
There are two systems that primarily mediate the stress response by applying an active
influence on cardiovascular function. These two systems are the hypothalamic-pituitary-
adrenocortical axis (HPA) and the sympatho-adrenomedullary system (SAS). However, cross-
sectional and longitudinal epidemiological data show that when chronic job stress disrupts the
HPA axis and the SAS, cardiovascular reactivity in response to stress are associated with
hypertension, coronary heart disease, and stroke (National Heart, Lung, and Blood Institute,
2004). In other words, because chronic stress makes your heart work too hard for too long it
increases susceptibility to coronary heart disease. Hypertension, which is elevated blood
pressure, and the release of cortisol from the adrenal medulla are the two major links between the
stress response and the development of coronary heart disease (Seaward, 2006).
Coronary heart disease, the leading cause of death in the United States, is a narrowing of
the small blood vessels that supply blood and oxygen to the heart caused by the buildup of
plaque in the arteries to your heart (MedlinePlus Medical Encyclopedia, 2014). The three stages
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of the disease are atherogenesis, atherosclerosis, and arteriosclerosis. During atherogenesis, the
initial stage, this is when a fatty streak appears on the inner lining of the artery wall.
Atherosclerosis is when the passage narrows due to the thickening of the plaque.
Arteriosclerosis, the third stage is when the arteries themselves become hard and possibly closed
from the flow of blood. If blood flow is stopped the heart muscle may show signs of oxygen
deprivation, resulting in either angina (chest pain) or death of myocardial tissue, and ultimately
ending in heart attack (Seaward, 2006). Common symptoms of the disease are angina and
shortness of breath. In cases of silent coronary heart disease, the disease may go unnoticed until a
person has signs or symptoms of a heart attack, heart failure, or an arrhythmia (National Heart,
Lung, and Blood Institute, 2011). In relation to stress, what is it that causes the plaque to build
up? Let’s begin with the first major link between stress and coronary heart disease, hypertension.
When chronic stress is present the fight-or-flight response, the term used to describe the
dynamics involved in the body’s physiological arousal to survive a threat, is triggered therefore
causing the body to attempt to shunt blood from its core to peripheral muscles thus causing the
release of epinephrine and norepinephrine from neural endings and the adrenal medulla,
aldosterone (increases blood volume by increasing water retention) from the adrenal cortex, and
vasopressin, or ADH (increase blood volume), into the bloodstream. Epinephrine and
norepinephrine are hormones made by the adrenal gland that increase heart rate and myocardial
contractility, which is the relative ability of the heart to eject a stroke volume at a given arterial
pressure and end-diastolic volume. They cause the heart to pump a larger supply of oxygenated
blood to the body’s muscles to produce energy and cause a change in total peripheral resistance
by constricting blood vessels of the gastrointestinal tract and dilating vessels to the body’s
periphery at the same time. The total effect of these hormones together is to raise blood pressure
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significantly above normal resting levels. This is what happens when stress is present. When
pressure is high vascular tissue is destroyed. The healing agent is cholesterol. However, if
pressure remains high there is no healing time. The release of cortisol from the adrenal medulla
is the second link between coronary heart disease and the stress response. This hormone
increases the level of free fatty acids carried by lipoproteins from the fat tissue sites into the
blood. Again this cholesterol can be used to repair vascular tissue, but when too much
cholesterol is present it can put a hindrance on the efficiency of the heart muscle by thickening
the passage and decreasing the diameter of the vessel for blood to pass through. The thicker the
inner lining of the artery wall, the more plaque can build up thus causing coronary heart disease.
The severity of the heart attack depends on the degree of blockage. The most severe result is
death (Seaward, 2006).
The idea of stress affecting your heart is a scary fact, especially knowing that it is
something that we deal with and will continue to deal with throughout our lifetime. We need to
know how to balance our feelings of stress where they do not overwhelm us and begin to affect
us physically. I can remember when I was a teenager and my grandmother would constantly yell
at me or be concerned about every little thing I did. My aunt would always tell her she needed to
calm down and stop worrying before she had a heart attack or stroke. I guess that statement had
more truth to it than I knew at the time. This just shows how all of the body’s systems and
functions are intertwined and that the simplest things that we do not think about can have
devastating effects on it.
There are a number of things that we can do to relieve or reduce stress. We could practice
meditation, get massages, do yoga, etc. It is important that we really engage in some type of
stress relief technique in order to reduce overload and prevent it from damaging our bodies.
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References
Engs, R. (1987, January 1). What stress is and health problems it can cause. Retrieved November
21, 2014, from http://www.indiana.edu/~engs/hints/stress1.htm
Fact Sheet on Stress. (n.d.). Retrieved November 21, 2014, from
http://www.nimh.nih.gov/health/publications/stress/index.shtml
Seaward, B. (2006). The Nature of Stress. In Managing Stress : Principles and Stategies for
Health and Well-Being (FIFTH ed.). Jones and Bartlett.
SEER Training Modules. (n.d.). Retrieved November 21, 2014, from
http://training.seer.cancer.gov/anatomy/cardiovascular/
The Editors of Encyclopædia Britannica. (n.d.). Homeostasis (biology). Retrieved November 21,
2014, from http://www.britannica.com/EBchecked/topic/270188/homeostasis
Parts of the Cardiovascular System. (2013, January 1). Retrieved November 21, 2014, from
http://www.physiologyinfo.org/mm/What-is-Physiology/Cardiovascular/Parts-of-the-
Cardiovascular-System.html
National Heart, Lung, and Blood Institute. (2004, August 9). Cardiovascular Consequences of
Chronic Stress. Retrieved November 21, 2014, from
https://www.nhlbi.nih.gov/research/reports/2004-heart-stress
Coronary heart disease: MedlinePlus Medical Encyclopedia. (2014, November 7). Retrieved
November 22, 2014, from http://www.nlm.nih.gov/medlineplus/ency/article/007115.htm
National Heart, Lung, and Blood Institute. (2011, May 1). What Are the Signs and Symptoms of
Coronary Heart Disease? Retrieved November 22, 2014, from
https://www.nhlbi.nih.gov/health/health-topics/topics/cad/signs
