STRESS IS NOT REALLY NERVOUS TENSION, SO WE will not dwell on the subject of nervousness and chronic anxiety, the cause of which must be determined and removed. Damaging or unpleasant stress, as Hans Selye states, is ‘‘stress with distress and this is always disagreeable.’’ Although stress can be associated with pleasant situations, it is more often produced by unpleasant stimuli. the word ‘‘stress’’ is derived from the old French and Middle English words for ‘‘distress’’; the first syllable was lost over the years.
I. EFFECTS ON THE CARDIOVASCULAR SYSTEM
There is no doubt that stress is awful. With the exception of severe pain and death, severe stress with distress is one of
the most difficult situations we have to face. Stress produces well-known reactions in the body such as an increase in blood pressure which causes small blood particles (platelets) to become sticky. the platelet particles stick together to form clumps or sludge, which can lead to formation of a blood clot in the coronary artery.
Trauma to arteries wreaks havoc like a silent killer. during the stress reaction, the arteries constrict under the influence of adrenaline and noradrenaline (epinephrine and norepinephrine). consequently both systolic and diastolic blood pressure increase. If the baseline blood pressure is usually 120/80, it can go up to 160/90 or from 145/95 to as high as 210/110. these elevated pressures, lasting only minutes, are injurious to the arteries, and when combined with the effects of excess adrenaline causing platelet sludging in the arteries, the death toll from heart attacks increases.
How does stress cause heart pain (angina) and damage to the heart and arteries? when the coronary arteries are narrowed by plaques of atheroma, chest pain may occur (see the chapter Angina). Chest pain is made worse by exertion such as walking up a hill. Pain at rest may occur, however, if the patient faces sudden emotional upset.
Stress causes adrenaline and noradrenaline release. these stress hormones cause the heart rate and blood pressure to increase, giving the heart more work to do (see Fig. 1). in some patients, adrenaline may cause platelets to clump onto plaques of atheroma, thus causing oxygen lack to that segment of heart muscle. this oxygen lack may or may not produce chest pain.
Moderate stress associated with simple daily activities can decrease the blood supply to the heart muscle in patients with coronary heart disease. in a study of 16 patients who had angina, the moderate stress of mental arithmetic caused oxygen lack to the heart muscle (myocardial ischemia) similar to that produced by exercise (see Fig. 2). in these patients a radioisotope material (rubidium-82) was injected into a vein, and when it reached the heart muscle photographs were taken. the dark areas in Fig. 2 represent the uptake of blood supply to the heart muscle. when the supply of blood is decreased, the area of muscle is poorly supplied with
blood, the presence of the rubidium-82 is reduced, and the area of darkness is diminished.
In a similar experiment, a patient who was having catheterization of his heart (coronary arteriogram) was asked to do mental arithmetic, asked to think of a past stressful situation, and saw the result of his catheter studies. His heart muscle function was determined during the test and showed no significant change with thinking of past stress, but showed a mild defect during mental arithmetic and severe defects in muscle function during the explanation and viewing of the findings of his heart catheter test.
A stressful situation causes the ‘‘emotional center’’ in the brain to trigger certain reactions (Fig. 1). the hypothala-mus sends signals to the pituitary gland and sympathetic nervous system, which lead to secretion of the ‘‘stress hormones’’ cortisone, adrenaline, and noradrenaline. Cortisone causes an increase in blood glucose and an increase in blood pressure.
As a result of a stressful situation (stressor), the inner compartment of the adrenal glands pours out adrenaline and noradrenaline and these compounds are involved in the ‘‘fight or flight’’ reaction. the external stimulus (stressor) is usually a condition that produces anger, fear, anxiety, and deprivation. Common stressors include the
death of a spouse, conflicts with others, and projects requiring a deadline. very often the stressor consists of words that are interpreted by the individual as harsh or hurtful, resulting in anger, hostility, humiliation, or resentment.
The body reacts in the same way regardless of the type or source of stress or unexpressed anger. Stress from an argument with the boss, fellow workers, a spouse, or others is the same as stress from being chased by an assailant. the fight for so-called prestige, recognition, and survival at work or at home goes on daily, and for many years you may bear the brunt of the stress.
When an individual is riled to the point of bursting, adrenaline in excess has been poured into the circulating blood. Visualize the adrenaline as little death potions that one may drink at work and for some, unfortunately, at home. Adrenaline is helpful in some situations; for example, when you want to flee from a charging bull or an assailant. these compounds increase the heart rate and blood pressure and increase the supply of blood containing glucose and oxygen to exercising muscles so that you are able to run. an excess of adrenaline and noradrenaline can be dangerous because these chemicals can over-stimulate the heart, disturb its electrical stability and, on rare occasions, lead to ventricular fibrillation.
Adrenaline causes a decrease in the ventricular fibrillation threshold and can precipitate ventricular fibrillation and cardiac arrest. Adrenaline causes platelets to clump, and if this occurs on a plaque of atheroma, pain can occur or a clot can develop. these compounds can also cause spasm of the coronary arteries, which in turn can produce chest pain and sometimes death, especially if the spasm occurs where the plaque partially blocks the artery.
Heart deaths are due to two major problems: (1) formation of a blood clot at the site of partial blockage by atherosclerosis in a coronary artery and (2) electrical disturbances that cause the heart to quiver and not contract (ventricular fibrillation). Sudden death is common, and the possibility cannot be excluded that severe acute stress may cause death by initiating a brain-adrenaline-heart interaction (see Fig. 1). the clumping of platelets can enlarge the plaque, and over a period of years the buildup of clot on a plaque can cause complete obstruction of the artery. Animal experiments lend support to this hypothesis. Rats exposed to sudden trauma develop blockage of the coronary arteries, which results in damage to the segments of the heart muscle (myocardial infarction). when rats were not physically traumatized but were stressed with nonphysical traumatic electric shocks, they developed clots in the coronary arteries and died. when rats were pretreated with drugs that prevented platelet clumping, such as aspirin or dipyridamole, and then
subjected to similar electric shocks, clots were prevented in the majority. If rats are pretreated with a beta-blocker, which blocks the dangerous effects of adrenaline, ventricular fibrillation is prevented and rats survive.
Experimentally, adrenaline or noradrenaline given intravenously can cause severe electrical disturbances and ventricular fibrillation. during a heart attack, there is an increase in noradrenaline in the heart muscle. when blood flow to the heart is reduced by atherosclerosis of the coronary artery, severe stress can more easily precipitate ventricular fibrillation.
When a coronary artery is suddenly blocked in dogs, severe quivering of the heart occurs in some. when the hypothalamus (in the brain) and sympathetic nervous systems are stimulated to produce noradrenaline at the same time that the coronary artery is blocked, quivering of the heart frequently occurs. Beta-blocking drugs block the actions of adrenaline and noradrenaline, and if dogs are pretreated with these drugs and the coronary artery is then blocked, the dangerous quivering of the heart can be prevented.
In a study involving 117 patients who were resuscitated from cardiac arrest, 25 reported that they had severe stress such as job and family conflicts within the 24 h prior to the cardiac arrest. Acute or prolonged (chronic) stress may produce severe damage to the coronary arteries. it must be remembered that atheroma of the arteries commonly produces no symptoms; it is a silent killer and after many years, a clot can develop on a ruptured atheromatous plaque. There is considerable evidence linking increased stickiness of platelets to the production of atheroma and blockage of arteries.
A. Stress and Sports
Do not push yourself excessively during a run if you are not a trained athlete. Do it if you feel great and enjoy it, and do not have to clench your jaws or tighten your facial muscles. If you have to push yourself to do an additional mile, then you may secrete excess adrenaline and noradrenaline and this takes its toll on your cardiovascular system throughout the years. Similarly, be careful not to be overly competitive when playing racquet sports.
B. the Symptoms and Signs of Stress
Sweatiness, especially on the forehead and skull, and under the armpits and on the palms owing to the presence of excess adrenaline.
Heart races and may easily pound.
Achiness in the head and neck, especially in the temples or eyes.
A feeling of turmoil or tightness in the chest or stomach as if there were butterflies in your stomach or there is a feeling of anguish, terror, fright, restlessness, agitation or tremulousness; feeling shaky, jittery, or weak all over.
Slurred speech with feelings of being unable to scream or talk for a few seconds.
Hostile, violent, full of rage and anger, and ready to fight back.
Difficulty sleeping with frequency of urination, indigestion, or sometimes diarrhea.
C. How to Handle Stress
Stress is a part of living and cannot be completely avoided. when you understand how traumatic stress can be to your heart and arteries, you may be motivated to develop techniques to deal with stress. Stress management is a complex subject, beyond the scope of this book. some of the ways that are indicated to cope with stress include mental diversion, techniques to develop a healthy self-concept, time management, progressive deep relaxation techniques, meditation, biofeedback, and exercise.
Stress is as important as the major ‘‘risk factors’’ (cholesterol, hypertension, diabetes, dyslipidemia, cigarette smoking), but it is difficult to prove this hypothesis scientifically. Stress, high blood cholesterol, hypertension, smoking, and blood-clotting factors work in concert in the genetically susceptible individual to produce atherosclerosis and, finally, a fatal or nonfatal heart attack. a stressor causes the sympathetic nervous system and adrenal glands to secrete stress hormones, which increase the work of the heart and cause platelet clumping that can sometimes cause a blood clot in the coronary artery. this chapter has outlined how excess adrenaline and noradrenaline alter the electrical stability of the heart, predisposing it to a high risk of a curious quivering (ventricular fibrillation) during which it fails to contract and sudden death may occur.
Humans are fortunate that the working of the body is such that the reaction caused by one chemical is often counterbalanced by other chemicals that are produced in the body. Nature does not always win, but it can, with a little help from you. it is important to develop strategies that may enable you to deal with various stressful
situations. Thus you will be able to handle stress and subdue the brain-adrenaline-heart-artery reaction described above.
II. TYPE a BEHAVIOR
Type a individuals have an impatient, time-conscious, achievement-striving personality, and they often seek out a hectic environment that provokes undue stress. Leisure brings a feeling of guilt, because their lives are an everlasting struggle against time toward achievement and recognition. the Type a individual takes on a project, including simple reading, with a certain violence. Speech is often harsh, explosive, or aggressive. when stressed, Type a individuals have been shown to release more adrenaline and noradrenaline and to have a greater rise in blood pressure than Type Bs. Type B people are easygoing, able to relax, and rarely carry work home or set deadlines. Most of us are mixtures of Type a and B. it is difficult for a Type a person to change, but with expert assistance, modification of lifestyle is possible.
Friedman and Rosenman have defined and established the concept of the Type a behavior pattern. They emphasized that if you have Type a behavior, you have an increased risk of coronary heart disease. Several studies have confirmed that a relationship exists between Type a behavior and risk of coronary heart disease. this occurs in both men and women independent of high blood cholesterol, hypertension, and smoking. the National Heart Lung Blood Institute has accepted the evidence regarding Type a behavior and increased risk of coronary heart disease.
The question of Type a behavior and increased risk of coronary heart disease remains controversial, however. the large Multiple Risk Factor Intervention Study and a small British study did not show any relationship between Type a behavior and coronary heart disease. a study reported in the new England Journal of Medicine found no relationship between Type a behavior and mortality from coronary heart disease in patients who had had a heart attack and were followed for three years. Commencing two weeks after their heart attack, 510 patients were followed. At the end of three years, death rate was not related to behavior, whether Type a or Type B. the mean Type a score did not differ significantly from the score of those who survived. the conclusion is: ‘‘Thus, we found no relation between type a behavior and the long-term outcome of acute myocardial infarction.