Everyone seems to know what “stress” is when they read or hear the word. When asked to define it, however, you’ll get as many definitions as there are people.
The National Institutes of Health define stress as the brain’s response to any demand. The American Academy of Family Physicians describes the stress response as the body’s attempt to defend itself. The American Psychological Association calls stress a reaction to a short-lived situation, which can be long-term, especially with relationships and in serious situations. Perhaps the most creative, if least illuminating, definition was offered by the highly respected British Medical Journal in 1951. Its contribution to the morass of medical conundrums: “Stress, in addition to being itself, was also the cause of itself, and the result of itself.”
This article contains a detailed description of the history of stress, how it affects the body, and how stress management techniques can help to reduce the burden.
“Stress in health and disease is medically, sociologically and philosophically the most meaningful subject for humanity that I can think of.” Hans H. Selye, MD
Hans Hugo Selye, MD (1907-1982) is usually, if wrongly, credited for originating the science of stress. Significant credit should also be given to Walter Bradford Cannon, MA, MD, (1871-1945).
Dr. Cannon grew up in Wisconsin and Minnesota. He entered Harvard in 1892, then Harvard Medical School in 1896. Cannon was attracted to the study of the physiology of emotion. He noticed that when his experimental animals were frightened or disturbed, the normal peristaltic waves in the stomach sometimes stopped abruptly. Upon graduation from medical school, Cannon became chair of the Harvard Department of Physiology.
Cannon began comprehensive research into the physiology of emotions — becoming the first major investigator in such research of the body’s systems. He showed that when an animal is strongly aroused, the nervous system, with the hormone adrenaline, mobilizes the animal for a “flight or fight” response. In his words, the “sympathico-adrenal system causes changes in blood supply, sugar availability, and the body’s clotting capacity in a ‘violent display of energy.'” Cannon, in 1915, summarized his work in a ground-breaking book: Bodily Changes in Pain, Hunger, Fear and Rage. (1, 2)
In 1917 Cannon’s expertise in physiology helped in the development of life-saving resuscitation procedures on the battle field, particularly in the prompt replacement of fluid lost from the bloodstream.
Cannon’s most important work after the war focused on the complexities of neurotransmission and homeostasis. He turned from the basic science aspect of physiology to its clinical application, becoming a major authority in the emerging field of psychosomatic medicine. (3)
Cannon died in 1945, a beloved and much honored investigator, teacher, mentor, and public role model. He was nominated for the Nobel prize but never received the honor. One of his admirers, Ralph W. Gerard, said in 1972 that despite being, he thought, unfairly overlooked, Cannon was “the greatest American physiologist … he was, indeed, a rather immortal hero.”
Hans Selye, MD was born in Vienna and studied medicine in Prague, Paris, and Rome. His interest in the body’s physiological response to illness and disease started in medical school, 1925. The curriculum included viewing patients in the early stages of a variety of infectious diseases. The professor noted that they looked and felt ill, had digestive problems and depression. He described the symptoms as “nonspecific” and useless in attempting to determine the germs responsible.
Selye wouldn’t accept that the symptoms were useless because they were nonspecific. He asked why a variety of disease states, such as allergies and infectious diseases, shared the same nonspecific symptoms. Selye noticed that the body adapts to external stressors in a biological pattern, so that the internal balance, or homeostasis, would be restored and maintained. In its attempt to retain homeostasis, the body uses particular hormones in the flight or fight response. Selye discovered that even if the body wants to control or reduce the stress, it still has limits. This limited ability to adapt to stress is even more noticeable when the body is exposed to the stressor continuously. Although discouraged by colleagues, Dr. Selye went on to discover and elucidate the triphasic (three-stage) role of hormones in the stress response. His findings formed the basis for what was named the General Adaptation Syndrome (GAS):
Stage 1: Alarm reaction
The immediate reaction to a stressor, the “flight or fight response”. The body perceives a stressor as a threat or danger and releases stress hormones, such as adrenaline and cortisol. These hormones enable the body to perform activities beyond the range of normal ability.
Stage 2: Resistance
This occurs after the body has responded to a stressor, and the stress level has been reduced or removed. The body’s defenses become weaker, as it needs to divert energy to the damaged tissues and lower the production of stress hormones. Although the body has shifted to the second phase of the GAS response, the body remains vigilant, especially when the stressors persist and the body is required to fight them continuously, although the response is weaker than the initial response.
Stage 3: Exhaustion
With long-term exposure to a stressor, the body starts to lose the ability to combat the stressor and to reduce its harmful impact; the adaptive energy is drained. It leads to “burnout” or “stress overload,” the creation of a milieu in which the individual is vulnerable to health problems. Catastrophic disease may occur.
Selye published more than 1600 articles and books about stress, including “The Stress of Life” and “Stress Without Distress.” With his more than 40 years dedicated to the study of stress, Selye concluded that health care must increasingly become the responsibility of the individual. He asserted that physicians must teach their patients to adopt habits that minimize stressful demands. Selye expressed his principles for healthy living as: find your own stress level, be an altruistic egoist and earn your neighbors’ love. (4, 8)
When the body is stressed, muscles become tense; it’s an automatic response, the body’s way of guarding against injury and pain. With the sudden onset of stress, the muscles tense all at once, then release their tension when the stress passes. Chronic stress causes the body to be in a constant state of guardedness. When muscles are tense over a long period of time, it may trigger other reactions of the body and promote stress-related disorders. Tension-type and migraine headaches are associated with chronic muscle tension in the area of the shoulders, neck, and head.
Millions of individuals suffer from chronic, painful conditions due to musculoskeletal disorders. Often, but not always, there may be an injury that sets off a chronic painful state. What determines whether or not an injured person goes on to suffer from chronic pain is how they respond to the injury. Individuals who are fearful of pain and reinjury, and who seek only a physical cause and cure for the injury, generally have a worse recovery than individuals who maintain a certain level of moderate, physician-supervised activity. Muscle tension, and eventually muscle atrophy, due to disuse of the body, promote chronic, stress-related musculoskeletal conditions.
Relaxation techniques have been shown to effectively reduce muscle tension, decrease the incidence of certain stress-related disorders, such as headache, and increase a sense of well-being.
Stress can affect your breathing patterns and your respiratory system. For those with asthma or a lung disease such as emphysema, getting the oxygen needed to breathe can be difficult. Some studies show that an acute stress, such as the death of a loved one, can actually trigger asthma attacks, in which the airways constrict. Stress can cause rapid breathing or hyperventilation that can bring on a panic attack in some individuals.
The heart and blood vessels work together to provide nourishment and oxygen throughout the body, and they play an important role in the stress response. Acute stress causes an increase in heart rate and stronger contractions of the heart muscle. The stress hormones (adrenaline, cortisol and noradrenaline) mediate the response. Blood vessels to the large muscles and the heart dilate, increasing the amount of blood flow to those parts of the body and elevating blood pressure. Once the acute stress is removed, the body returns to its normal state.
Chronic, long-term stress can contribute to problems of the heart and blood vessels. The consistent increase in blood pressure and heart rate, as well as the higher level of circulating stress hormones, take a toll on health. They increase the risk of hypertension (high blood pressure), heart attack and stroke.
Recurrent acute and persistent chronic stress can contribute to inflammation in the circulatory system, especially the coronary arteries. It is believed that it’s such inflammation that ties stress to heart attacks. Chronic stress can also elevate total cholesterol levels.
The risk of heart disease associated with stress may differ with women in accordance with pre- or post-menopausal states. Levels of estrogen in pre-menopausal women help blood vessels respond better during stress, having a protective effect against heart disease. Post-menopausal women lose the protective level of estrogen, putting them at greater risk for the effects of stress in heart disease. (5)
The stress response is automatic, developed in our ancestors to protect them from predators. Faced with danger, stress hormones flood the body, boosting energy, and readying it to fight the problem. At one time, the threat we faced was being attacked by predators. That’s less likely now, but people still face multiple challenges every day, associated with work, family and finances. Regardless of the source of the stress, the body reacts in much the same way.
Short-lived stress can have an impact: minor, such as a stomach-ache, or major, with acute stress such as a natural disaster. Sudden emotional distresses, especially anger, can trigger heart attacks, irregular heart beats, even sudden death. Such reactions happen mostly in people with known heart disease, but some people don’t know they have a problem until acute stress causes a heart attack or worse. (6)
When stress interferes with daily life for an extended period of time, it gradually takes a greater and greater toll on the body and mind, leading to fatigue, inability to concentrate, and irritable mood. Chronic stress can cause disease, either because of changes in the body or because of the overeating, smoking, and other high-risk behaviors people employ to cope with stress. Job strain is associated with increased risk of coronary artery disease. Depression and low levels of social support increase risk for cardiovascular disease. When illness occurs, stress can make it harder to recover. (7)
Reducing stress makes a person feel better immediately, and can help protect health long-term. In one study examining the association between feelings like happiness, joy, contentment and enthusiasm, and the development of coronary artery disease, it was demonstrated that as positive emotions increase, the risk of coronary artery disease decreases. (7)
Some simple methods for reducing stress include:
- Identify what’s causing the stress
Be aware of your state of mind throughout the day. If you feel stressed, write down the cause, your thoughts and mood. When you know what’s bothering you, you can develop a plan for coping. That may mean more realistic expectations of yourself and others, and perhaps asking for help with your job or your home. Determine your priorities and eliminate nonessential tasks. Make sure you have some time each day that is your own and nobody else’s.
- Build strong relationships
Relationships can be a source of stress or serve as stress relievers. Reach out to family members and close friends. They can offer practical advice, emotional support and perhaps a different perspective on the stressor.
- Walk away
When you’re angry, walk away and reconsider before you react.
Physical activity can help you work off steam. It’s a natural stress-reliever and increases endorphins. Commit to a daily walk or other form of exercise.
- Rest your mind
Stress interferes with sleep. Practice good sleep hygiene and try to get the recommended 7-8 hours of sleep per night. Cut back on caffeine and stimulating activity. Eliminate the use of computers or television before bed; even better, take them out of the bedroom entirely. Yoga and relaxation exercises will help to reduce stress and boost the immune system.
- Get help from a professional
A mental health professional can teach you how to identify situations or behaviors that act as stressors. Develop an action plan for change.
American Psychological Association: Mind-body health interactive
American Academy of Family Physicians: How to cope better with life’s challenges
1) Fleming D., Walter Bradford Cannon, Dictionary of American Biography. Supplement 3. New York, NY: Charles Scribners Son; 1973:133-137.
2) Cannon, WB. Bodily Changes in Pain, Hunger, Fear and Rage. New York, NY; D. Appleton & Company; 1915.
3) Cannon, WB. The role of emotions in disease. Ann Intern Med 1936;9:1453-1465.
4) Sarah Mae Sincero (July 10, 2012). General Adaptation Syndrome, retrieved 2014 from: http://explorable.com/general-adaptation-syndrome.
5) Krantz, D.S., Whittaker, K.S. & Sheps, D.S., 2011 “Psychosocial factors for coronary artery disease: Pathophysiologic mechanisms.” in Heart and Mind: Evolution of cardiac physiology. Washington, D.C.
6) Krantz, D.S. & McCeney, M.K. (2002). Effects of physiological and social factors on organic disease: A critical assessment of research on coronary heart disease. Annual Review of Psychology, 53, 341-369.
7) Davidson, K.W., Mostofsky, E., Whang, W. (2010). “Don’t worry, be happy: Positive affect and reduced 10 year incident coronary artery disease; The Canadian Nova Scotia Health Survey” European Heart Journal, 31, 1065-1070.
8) Selye, HH. Stress of Life, Stress Without Distress.