Although much remains to be learned, it is clear that people who have unresolved chronic stress in their lives or who handle stressors poorly are at risk for a wide range of health problems. In the short term, the problem might be just a cold, a stiff neck, or a stomachache. Over the long term, the problems can be more severe—cardiovascular disease (CVD), high blood pres- sure, impaired immune function, or a host of other problems.
Cardiovascular Disease During the stress response, heart rate increases and blood vessels constrict, causing blood stage may experience headaches, indigestion, anxiety, and dis-
rupted eating or sleep patterns.
• Resistance. With continued stress, the body develops a new level of homeostasis in which it is more resistant to dis- ease and injury than usual. In this stage, a person can cope with normal life and added stress.
• Exhaustion. Th e fi rst two stages of GAS require a great deal of energy. If a stressor persists, or if several stress- ors occur in succession, general exhaustion sets in. Th is is not the sort of exhaustion you feel after a long, busy day. Rather, it’s a life-threatening type of physiological exhaustion.
Allostatic Load
Although the GAS model is still viewed as a key conceptual contribution to the understanding of stress, some aspects of it are considered outdated. For example, increased suscepti- bility to disease after repeated or prolonged stress is now thought to be due to the eff ects of the stress response itself rather than to a depletion of resources (exhaustion state). In particular, long-term overexposure to stress hormones such as cortisol has been linked with health problems. Further, although physical stress reactions promote homeostasis (re- sistance stage), they also have negative eff ects on the body. Th e long-term wear and tear of the stress response is called the allostatic load. A person’s allostatic load depends on many factors, including genetics, life experiences, and emotional and behavioral responses to stressors. A high al- lostatic load may be due to frequent stressors, poor adapta- tion to common stressors, an inability to shut down the stress response, or imbalances in the stress response of diff erent body systems. High allostatic load is linked to heart disease, hypertension, obesity, and reduced brain and immune system functioning. In other words, when your allostatic load ex- ceeds your ability to cope, you are more likely to get sick.
Psychoneuroimmunology
One of the most fruitful areas of current research into the relationship between stress and disease is psychoneuroim- munology (PNI). PNI is the study of the interactions among the nervous system, the endocrine system, and the immune system. Th e underlying premise of PNI is that stress, through the actions of the nervous and endocrine systems, impairs the immune system and thereby aff ects health.
A complex network of nerve and chemical connections exists between the nervous, endocrine, and immune systems. In general, increased levels of cortisol are linked to a de- creased number of immune system cells, or lymphocytes (see Chapter 13 for more about the immune system). Epineph- rine appears to promote the release of lymphocytes but at the same time reduces their effi ciency. Scientists have identifi ed hormone-like substances called neuropeptides that appear to translate stressful emotions into biochemical events, some of which impact the immune system, providing a physical link between emotions and immune function.
Ask Yourself
Ask Yourself
QUESTIONS FOR CRITICAL THINKING AND REFLECTION
Have you ever been so stressed that you felt ill in some way? If so, what were your symptoms? How did you handle them? Did the experience aff ect the way you reacted to other stressful events?
allostatic load The long-term negative impact of the stress response on the body.
psychoneuroimmunology (PNI) The study of the interactions among the nervous, endocrine, and immune systems.
acute stress Stress immediately following a stressor; may last only minutes or may turn into chronic stress.
chronic stress Stress that continues for days, weeks, or longer.
S T R E S S A N D H E A L T H 29 both. Stress has been found to contribute to psychological problems such as depression, panic attacks, anxiety, eating disorders, and posttraumatic stress disorder (PTSD). PTSD, which affl icts war veterans, rape and child abuse survivors, and others who have suff ered or witnessed severe trauma, is characterized by nightmares, fl ashbacks, and a diminished capacity to experience or express emotion.
Altered Immune Function PNI research helps explain how stress aff ects the immune system. Some of the health problems linked to stress-related changes in immune function include vulnerability to colds and other infections, asthma and allergy attacks, susceptibility to cancer, and fl are-ups of chronic diseases such as genital herpes and HIV infection.
Headaches More than 45 million Americans suff er from chronic, recurrent headaches. Headaches come in various types but are often grouped into the three following categories:
• Tension headaches. Approximately 90% of all head- aches are tension headaches, characterized by a dull, steady pain, usually on both sides of the head. It may feel as though a band of pressure is tightening around the head, and the pain may extend to the neck and shoulders. Acute tension headaches may last from hours to days, while chronic tension headaches may occur almost every day for months or even years. Psychological stress, poor posture, and immobility are the leading causes of tension headaches. Th ere is no cure, but the pain can sometimes be relieved with over-the-counter painkillers and with therapies such as massage, acupuncture, relaxation, hot or cold showers, and rest.
• Migraine headaches. Migraines typically progress through a series of stages lasting from several minutes to sev- eral days. Th ey may produce a variety of symptoms, including throbbing pain that starts on one side of the head and may spread, heightened sensitivity to light, visual disturbances such as fl ashing lights or temporary blindness, nausea, dizziness, and fatigue. About 70% of migraine suff erers are women, and migraine headaches may have a genetic component. Potential triggers include menstruation, stress, fatigue, atmospheric changes, bright light, specifi c sounds or odors, and certain foods. Th e frequency of attacks varies from a few in a lifetime to several per week. Aerobic exercise is frequently recom- mended to reduce the frequency and severity of migraines, but evidence for the eff ectiveness of exercise as a treatment is mixed. For some people, exercise can trigger a migraine.
• Cluster headaches. Cluster headaches are extremely severe headaches that cause intense pain in and around one eye. Th ey usually occur in clusters of one to three headaches each day over a period of weeks or months, alternating with periods of re- mission in which no headaches occur. About 90% of people with cluster headaches are male. Th ere is no known cause or cure for cluster headaches, but a number of treat- ments are available. During cluster periods, pressure to rise. Chronic high blood pressure is a major cause
of atheroscl e rosis, a disease in which blood vessels become damaged and caked with fatty deposits. Th ese deposits can block arteries, causing heart attacks and strokes. Th e stress response can precipitate a heart attack in someone with ath- erosclerosis. Th e stress response can also cause stress cardio- myopathy (“broken heart syndrome”), a condition that mimics a heart attack but doesn’t damage the heart.
Certain emotional responses may increase a person’s risk of CVD. As described earlier, people who tend to react to situations with anger and hostility are more likely to have heart attacks than are people with less explo-
sive, more trusting personalities.
Psychological Problems The hor- mones and other chemicals released during the stress response cause emotional as well as physical changes. Stress also activates the enzyme PKC, which infl uences the brain’s prefrontal cortex. Excess PKC can negatively aff ect focus, judgment, and the ability to think clearly. Moreover, many stressors are inherently anxiety-producing, depressing, or
Ongoing stress has been shown to make people more vulnerable to everyday ailments, such as colds and allergies.
11% of adult
Americans suff er
serious
psychological
distress.
—SAMHSA, 2009 QUICK STATS• Interpersonal stress. Most students are more than just students; they are also friends, children, employees, spouses, parents, and so on. Managing relationships while juggling the rigors of college life can be daunting, especially if some friends or family members are less than supportive.
• Time pressures. Class schedules, assignments, and deadlines are an inescapable part of college life. But these time pressures can be drastically compounded for students who also have job or family responsibilities.
• Financial concerns. Th e majority of college students need fi nancial aid not just to cover the cost of tuition but also to survive from day to day while in school. For many, college life isn’t possible without a job, and the pressure to stay afl oat fi nancially competes with academic and other stressors.
• Worries about the future. As college comes to an end, students face life after college. Th is means thinking about a career, choosing a place to live, and leaving the friends and routines of school behind.
As mentioned earlier, test anxiety is a source of stress for many students. To learn some proven techniques for over- coming test anxiety, see the Behavior Change Strategy at the end of this chapter.