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Ophthalmology => High Blood Pressure => Stress
Stress
INTRODUCTION
Stress (psychology), an unpleasant state of emotional and physiological arousal that people experience in situations that they perceive as dangerous or threatening to their well-being. The word stress means different things to different people. Some people define stress as events or situations that cause them to feel tension, pressure, or negative emotions such as anxiety and anger. Others view stress as the response to these situations. This response includes physiological changes-such as increased heart rate and muscle tension-as well as emotional and behavioral changes. However, most psychologists regard stress as a process involving a person's interpretation and response to a threatening event.
Stress is a common experience. We may feel stress when we are very busy, have important deadlines to meet, or have too little time to finish all of our tasks. Often people experience stress because of problems at work or in social relationships, such as a poor evaluation by a supervisor or an argument with a friend. Some people may be particularly vulnerable to stress in situations involving the threat of failure or personal humiliation. Others have extreme fears of objects or things associated with physical threats-such as snakes, illness, storms, or flying in an airplane-and become stressed when they encounter or think about these perceived threats. Major life events, such as the death of a loved one, can cause severe stress.
Stress can have both positive and negative effects. Stress is a normal, adaptive reaction to threat. It signals danger and prepares us to take defensive action. Fear of things that pose realistic threats motivates us to deal with them or avoid them. Stress also motivates us to achieve and fuels creativity. Although stress may hinder performance on difficult tasks, moderate stress seems to improve motivation and performance on less complex tasks. In personal relationships, stress often leads to less cooperation and more aggression.
If not managed appropriately, stress can lead to serious problems. Exposure to chronic stress can contribute to both physical illnesses, such as heart disease, and mental illnesses, such as anxiety disorders. The field of health psychology focuses in part on how stress affects bodily functioning and on how people can use stress management techniques to prevent or minimize disease.
SOURCES OF STRESS
The circumstances that cause stress are called stressors. Stressors vary in severity and duration. For example, the responsibility of caring for a sick parent may be an ongoing source of major stress, whereas getting stuck in a traffic jam may cause mild, short-term stress. Some events, such as the death of a loved one, are stressful for everyone. But in other situations, individuals may respond differently to the same event-what is a stressor for one person may not be stressful for another. For example, a student who is unprepared for a chemistry test and anticipates a bad grade may feel stress, whereas a classmate who studies in advance may feel confident of a good grade. For an event or situation to be a stressor for a particular individual, the person must appraise the situation as threatening and lack the coping resources to deal with it effectively.
Stressors can be classified into three general categories: catastrophic events, major life changes, and daily hassles. In addition, simply thinking about unpleasant past events or anticipating unpleasant future events can cause stress for many people.
° Catastrophes
A catastrophe is a sudden, often life-threatening calamity or disaster that pushes people to the outer limits of their coping capability. Catastrophes include natural disasters-such as earthquakes, tornadoes, fires, floods, and hurricanes-as well as wars, torture, automobile accidents, violent physical attacks, and sexual assaults. Catastrophes often continue to affect their victims' mental health long after the event has ended. For example, in 1972 a dam burst and flooded the West Virginia mining town of Buffalo Creek, destroying the town. Two years after the disaster, most of the adult survivors continued to show emotional disturbances. Similarly, most of the survivors of concentration camps in World War II (1939-1945) continued to experience nightmares and other symptoms of severe emotional problems long after their release from the camps.
° Major Life Changes
The most stressful events for adults involve major life changes, such as death of a spouse or family member, divorce, imprisonment, losing one's job, and major personal disability or illness. For adolescents, the most stressful events are the death of a parent or a close family member, divorce of their parents, imprisonment of their mother or father, and major personal disability or illness. Sometimes, apparently positive events can have stressful components. For example, a woman who gets a job promotion may receive a higher salary and greater prestige, but she may also feel stress from supervising coworkers who were once peers. Getting married is usually considered a positive experience, but planning the wedding, deciding whom to invite, and dealing with family members may cause couples to feel stressed.
° Daily Hassles
Much of the stress in our lives results from having to deal with daily hassles pertaining to our jobs, personal relationships, and everyday living circumstances. Many people experience the same hassles every day. Examples of daily hassles include living in a noisy neighborhood, commuting to work in heavy traffic, disliking one's fellow workers, worrying about owing money, waiting in a long line, and misplacing or losing things. When taken individually, these hassles may feel like only minor irritants, but cumulatively, over time, they can cause significant stress. The amount of exposure people have to daily hassles is strongly related to their daily mood. Generally, the greater their exposure is to hassles, the worse is their mood. Studies have found that one's exposure to daily hassles is actually more predictive of illness than is exposure to major life events.
EFFECTS OF STRESS
A person who is stressed typically has anxious thoughts and difficulty concentrating or remembering. Stress can also change outward behaviors. Teeth clenching, hand wringing, pacing, nail biting, and heavy breathing are common signs of stress. People also feel physically different when they are stressed. Butterflies in the stomach, cold hands and feet, dry mouth, and increased heart rate are all physiological effects of stress that we associate with the emotion of anxiety.
° The Stress Response
When a person appraises an event as stressful, the body undergoes a number of changes that heighten physiological and emotional arousal. First, the sympathetic division of the autonomic nervous system is activated. The sympathetic division prepares the body for action by directing the adrenal glands to secrete the hormones epinephrine (adrenaline) and norepinephrine (noradrenaline). In response, the heart begins to beat more rapidly, muscle tension increases, blood pressure rises, and blood flow is diverted from the internal organs and skin to the brain and muscles. Breathing speeds up, the pupils dilate, and perspiration increases. This reaction is sometimes called the fight-or-flight response because it energizes the body to either confront or flee from a threat.
Another part of the stress response involves the hypothalamus and the pituitary gland, parts of the brain that are important in regulating hormones and many other bodily functions. In times of stress, the hypothalamus directs the pituitary gland to secrete adrenocorticotropic hormone. This hormone, in turn, stimulates the outer layer, or cortex, of the adrenal glands to release glucocorticoids, primarily the stress hormone cortisol (see Hydrocortisone). Cortisol helps the body access fats and carbohydrates to fuel the fight-or-flight response.
Canadian scientist Hans Selye was one of the first people to study the stress response. As a medical student, Selye noticed that patients with quite different illnesses shared many of the same symptoms, such as muscle weakness, weight loss, and apathy. Selye believed these symptoms might be part of a general response by the body to stress. In the 1930s Selye studied the reactions of laboratory rats to a variety of physical stressors, such as heat, cold, poisons, strenuous exercise, and electric shock. He found that the different stressors all produced a similar response: enlargement of the adrenal glands, shrinkage of the thymus gland (a gland involved in the immune response), and bleeding stomach ulcers.
Selye proposed a three-stage model of the stress response, which he termed the general adaptation syndrome. The three stages in Selye's model are alarm, resistance, and exhaustion. The alarm stage is a generalized state of arousal during the body's initial response to the stressor. In the resistance stage, the body adapts to the stressor and continues to resist it with a high level of physiological arousal. When the stress persists for a long time, and the body is chronically overactive, resistance fails and the body moves to the exhaustion stage. In this stage, the body is vulnerable to disease and even death.
° Disease
Physicians increasingly acknowledge that stress is a contributing factor in a wide variety of health problems. These problems include cardiovascular disorders such as hypertension (high blood pressure); coronary heart disease (coronary atherosclerosis, or narrowing of the heart's arteries); and gastrointestinal disorders, such as ulcers. Stress also appears to be a risk factor in cancer, chronic pain problems, and many other health disorders. See Stress-Related Disorders.
Researchers have clearly identified stress, and specifically a person's characteristic way of responding to stress, as a risk factor for cardiovascular diseases. The release of stress hormones has a cumulative negative effect on the heart and blood vessels. Cortisol, for example, increases blood pressure, which can damage the inside walls of blood vessels. It also increases the free fatty acids in the bloodstream, which in turn leads to plaque buildup on the lining of the blood vessels. As the blood vessels narrow over time it becomes increasingly difficult for the heart to pump sufficient blood through them.
People with certain personality types seem to be physiologically overresponsive to stress and therefore more vulnerable to heart disease. For example, the so-called Type A personality is characterized by competitiveness, impatience, and hostility. When Type A people experience stress, their heart rate and blood pressure climb higher and recovery takes longer than with more easygoing people. The most "toxic" personality traits of Type A people are frequent reactions of hostility and anger. These traits are correlated with an increased risk of coronary heart disease.
Stress also appears to influence the development of cancer, but the relationship is not as well established as it is for cardiovascular diseases. There is a moderate positive correlation between extent of exposure to life stressors and cancer-the more stressors, the greater the likelihood of cancer. In addition, a tendency to cope with unpleasant events in a rigid, unemotional manner is associated with the development and progression of cancer.
° Decreased Immune Response
Ordinarily the immune system is a marvel of precision. It protects the body from disease by seeking out and destroying foreign invaders, such as viruses and bacteria. But there is substantial evidence that stress suppresses the activity of the immune system, leaving an organism more susceptible to infectious diseases. An organism with a weakened immune system is also less able to control naturally occurring mutant cells that overproduce and lead to cancer.
Numerous studies have linked stress with decreased immune response. For example, when laboratory animals are physically restrained, exposed to inescapable electric shocks, or subjected to overcrowding, loud noises, or maternal separation, they show decreased immune system activity. Researchers have reported similar findings for humans. One study, for example, found weakened immune response in people whose spouses had just died. Other studies have documented weakened immune responses among students taking final examinations; people who are severely deprived of sleep; recently divorced or separated men and women; people caring for a family member with Alzheimer's disease; and people who have recently lost their jobs.
Stress appears to depress immune function in two main ways. First, when people experience stress, they more often engage in behaviors that have adverse effects on their health: cigarette smoking, using more alcohol or drugs, sleeping less, exercising less, and eating poorly. In addition, stress may alter the immune system directly through hormonal changes. Research indicates that glucocorticoids-hormones that are secreted by the adrenal glands during the stress response-actively suppress the body's immune system.
At one time scientists believed the immune system functioned more or less as an independent system of the body. They now know that the immune system does not operate by itself, but interacts closely with other bodily systems. The field of psychoneuroimmunology focuses on the relationship between psychological influences (such as stress), the nervous system, and the immune system.
° Mental Illness
Stress influences mental health as well as physical health. People who experience a high level of stress for a long time-and who cope poorly with this stress-may become irritable, socially withdrawn, and emotionally unstable. They may also have difficulty concentrating and solving problems. Some people under intense and prolonged stress may start to suffer from extreme anxiety, depression, or other severe emotional problems. Anxiety disorders caused by stress may include generalized anxiety disorder, phobias, panic disorder, and obsessive-compulsive disorder. People who survive catastrophes sometimes develop an anxiety disorder called post-traumatic stress disorder. They reexperience the traumatic event again and again in dreams and in disturbing memories or flashbacks during the day. They often seem emotionally numb and may be easily startled or angered.
COPING WITH STRESS
Coping with stress means using thoughts and actions to deal with stressful situations and lower our stress levels. Many people have a characteristic way of coping with stress based on their personality. People who cope well with stress tend to believe they can personally influence what happens to them. They usually make more positive statements about themselves, resist frustration, remain optimistic, and persevere even under extremely adverse circumstances. Most importantly, they choose the appropriate strategies to cope with the stressors they confront. Conversely, people who cope poorly with stress tend to have somewhat opposite personality characteristics, such as lower self-esteem and a pessimistic outlook on life.
° Coping Strategies
Psychologists distinguish two broad types of coping strategies: problem-focused coping and emotion-focused coping. The goal of both strategies is to control one's stress level. In problem-focused coping, people try to short-circuit negative emotions by taking some action to modify, avoid, or minimize the threatening situation. They change their behavior to deal with the stressful situation. In emotion-focused coping, people try to directly moderate or eliminate unpleasant emotions. Examples of emotion-focused coping include rethinking the situation in a positive way, relaxation, denial, and wishful thinking.
To understand these strategies, consider the example of a premed student in college who faces three difficult final examinations in a single week. She knows she must get top grades in order to have a chance at acceptance to medical school. This situation is a potential source of stress. To cope, she could organize a study group and master the course materials systematically (problem-focused coping). Or she could decide that she needs to relax and collect herself for an hour or so (emotion-focused coping) before proceeding with an action plan (problem-focused coping). She might also decide to watch television for hours on end to prevent having to think about or study for her exams (emotion-focused coping).
In general, problem-focused coping is the most effective coping strategy when people have realistic opportunities to change aspects of their situation and reduce stress. Emotion-focused coping is most useful as a short-term strategy. It can help reduce one's arousal level before engaging in problem-solving and taking action, and it can help people deal with stressful situations in which there are few problem-focused coping options.
° Social Support
Support from friends, family members, and others who care for us goes a long way in helping us to get by in times of trouble. Social support systems provide us with emotional sustenance, tangible resources and aid, and information when we are in need. People with social support feel cared about and valued by others and feel a sense of belonging to a larger social network.
A large body of research has linked social support to good health and a superior ability to cope with stress. For example, one long-term study of several thousand California residents found that people with extensive social ties lived longer than those with few close social contacts. Another study found that heart-attack victims who lived alone were nearly twice as likely to have another heart attack as those who lived with someone. Even the perception of social support can help people cope with stress. Studies have found that people's appraisal of the availability of social support is more closely related to how well they deal with stressors than the actual amount of support they receive or the size of their social network.
Research also suggests that the companionship of animals can help lower stress. For example, one study found that in times of stress, people with pet dogs made fewer visits to the doctor than those without pets.
° Biofeedback
Biofeedback is a technique in which people learn voluntary control of stress-related physiological responses, such as skin temperature, muscle tension, blood pressure, and heart rate. Normally, people cannot control these responses voluntarily. In biofeedback training, people are connected to an instrument or machine that measures a particular physiological response, such as heart rate, and feeds that measurement back to them in an understandable way. For example, the machine might beep with each heartbeat or display the number of heartbeats per minute on a digital screen. Next, individuals learn to be sensitive to subtle changes inside their body that affect the response system being measured. Gradually, they learn to produce changes in that response system-for example, to voluntarily lower their heart rate. Typically individuals use different techniques and proceed by trial and error until they discover a way to produce the desired changes.
Scientists do not understand the mechanisms by which biofeedback works. Nonetheless, it has become a widely used and generally accepted technique for producing relaxation and lowering physiological arousal in patients with stress-related disorders. One use of biofeedback is in the treatment of tension headaches. By learning to lower muscle tension in the forehead, scalp, and neck, many tension headache sufferers can find long-term relief.
° Relaxation
In addition to biofeedback, two other major methods of relaxation are progressive muscular relaxation and meditation. Progressive muscular relaxation involves systematically tensing and then relaxing different groups of skeletal (voluntary) muscles, while directing one's attention toward the contrasting sensations produced by the two procedures. After practicing progressive muscular relaxation, individuals become increasingly sensitive to rising tension levels and can produce the relaxation response during everyday activities (often by repeating a cue word, such as calm, to themselves).
Meditation, in addition to teaching relaxation, is designed to achieve subjective goals such as contemplation, wisdom, and altered states of consciousness. Some forms have a strong Eastern religious and spiritual heritage based in Zen Buddhism and yoga. Other varieties emphasize a particular lifestyle for practitioners. One of the most common forms of meditation, Transcendental Meditation, involves focusing attention on and repeating a mantra, which is a word, sound, or phrase thought to have particularly calming properties.
Both progressive muscle relaxation and meditation reliably reduce stress-related arousal. They have been used successfully to treat a range of stress-related disorders, including hypertension, migraine and tension headaches, and chronic pain.
° Aerobic Exercise
Aerobic exercise-such as running, walking, biking, and skiing-can help keep stress levels down. Because aerobic exercise increases the endurance of the heart and lungs, an aerobically fit individual will have a lower heart rate at rest and lower blood pressure, less reactivity to stressors, and quicker recovery from stressors. In addition, studies show that people who exercise regularly have higher self-esteem and suffer less from anxiety and depression than comparable people who are not aerobically fit. The American College of Sports Medicine recommends exercising three to four times a week for at least 20 minutes to reduce the risk of cardiovascular disease.
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