Mandatory Writing Assignment/Research Project

Stress and Your Health

For decades, psychologists have 

e been trying to understand how stress impacts human health. Early in the 1960s, the field of  health psychology  began to gather momentum, exploring the biological, psychological, and social factors that contribute to health and illness. Health psychology seeks to explain how food choices, social interactions, and living environments affect our predisposition to illness. Research in this field informs public policy and health education, leading to changes in health-related guidelines and the promotion of positive eating and exercise habits. Health psychologists also study the impact of personality factors, coping style, cognitive appraisal, poverty, culture, social support, and religion—all topics addressed in this chapter ( INFOGRAPHIC 12.3 ).

Synonyms

health psychology behavioral medicine

TABLE 12.1 LIVING LONGER

Characteristics	Benefits	Application
Innate movement	You don’t have to join a gym or compete in triathlons; every physical activity counts.	Walk to work or to the store, bike to school. Find ways to incorporate natural movement into your daily life.
Find meaning	Purpose outside of your job makes it easier to wake up each morning; knowing your purpose can extend life expectancy.	Find your motivation for life. What energizes you?
Slow down	Stress affects everyone, but slowing down reduces inflammation that can lead to many age-related illnesses.	Meditate, pray, or nap.
“80% rule”	Helps prevent weight gain and overeating.	Stop eating when you feel 80% full.
Eat more plants	Inexpensive source of complex carbs, fiber, and protein.	Eat lean; make beans and vegetables the bulk of your diet. Limit your intake of meat.
Social support	Healthy friends encourage healthy behaviors.	Surround yourself with people who encourage healthy living and happiness.
Family first	Time spent with grandparents, parents, and a committed life partner can extend life expectancy.	Create strong family ties, and keep loved ones in close proximity.

Can you live a long, healthy, low-stress life? It is possible, according to Dan Buettner, especially if you adopt the characteristics listed above, which are commonly observed in “blue zone” regions of the world. Information from Buettner, 2015.

ACROSS THE WORLD

The “Blue Zones”

Can the place you reside contribute to your level of stress and overall health? A group of researchers working with the National Geographic Society set out to identify regions of the world with the highest number of people living over 100 years. (These locations came to be called “blue zones” because someone used a blue pen to circle one of them on a map; Buettner, 2015).

“BLUE ZONES” OFFER CLUES ON HOW TO LIVE A LONG AND HEALTHY LIFE.

To qualify as a blue zone, an area had to be inhabited by people reaching old age without health issues such as diabetes, cancer, obesity, and heart trouble. Five areas in the world made the cut: Ikaria, Greece; Okinawa, Japan; Ogliastra Region, Sardinia; Loma Linda, California; Nicoya Peninsula, Costa Rica. What unique features of these areas allow for such longevity (Buettner, 2015; see  TABLE 12.1 )?

Are these characteristics for a long, healthy life limited to blue zones? Apparently not. If you stay physically active, limit stress, eat locally grown foods, and surround yourself with strong social support, you, too, might live to be a centenarian (Govindaraju, Atzmon, & Barzilai, 2015; Poulain, Herm, & Pes, 2013). 

Is Stress Making You Sick?

LO 7 Explain how stressors relate to health problems.

Before we further explore the connection between stress and illness, we must understand how the body deals with illness. Let’s take a side trip into introductory biology and learn about the body’s main defense against disease—the immune system ( FIGURE 12.3 ). The immune system is made up of the spleen, lymph nodes, and bone marrow. When disease-causing invaders threaten the body, the immune system deploys a special army of white blood cells called  lymphocytes.  Lymphocytes are produced in bone marrow, and their job is to battle enemies such as viruses and bacteria. When the body is expending its resources to deal with an ongoing stressor, the immune system is less powerful, and the work of lymphocytes is compromised.

Like a platoon of soldiers, the immune system has a defense team to fight off invaders. Should the intruder(s) get past the skin, the macrophages (“big eaters”) are ready to attack. These cells hunt and consume invaders as well as worn-out cells in the body. Cells that have been affected by invaders, such as viruses and cancer, are the targets of natural killer cells (NK. cells), which inject compromised cells with a deadly chemical. In addition, NK cells release a protein that prevents the infection from spreading to other cells. In some cases, the body must call on its “special ops” teams. These are the B lymphocytes and T lymphocytes. The B lymphocytes mature in the bone marrow and produce antibodies that chemically inhibit bacteria. The T lymphocytes mature in the thymus and play an integral role in fighting cancer, viruses, and other disease-causing agents that the B lymphocytes have not been successful in warding off (Matloubain et al., 2004; Straub, 2014).

Synonyms

B lymphocytes B cells

T lymphocytes T cells

With that immunology lesson under our belt, let’s examine some of the diseases thought to be associated with stressors.

Man: B2M Productions/Getty Images. T lymphocytes & B lymphocytes: Steve Gschmeissner/Science Source. Natural killer cell & macrophage: Eye of Science/Science Source.

FIGURE 12.3

The Immune System

Our immunity derives from a complex system involving structures and organs throughout the body that support the work of specialized cell types to keep us healthy.

Text attached to the thymus reads “T lymphocytes (pink), which fight viruses, cancer, and other invaders, mature in the thymus.” A microscopic image under the text shows the T lymphocytes as small round balls that attach to a larger body, which is the invader. Text attached to the spleen reads “The spleen stores pro-immune cells and filters out successfully destroyed invaders.” Text attached to bone marrow in a leg bone reads “B lymphocytes, which fight bacteria, mature in the bone marrow.” A microscopic image above the text shows a B lymphocyte as a round structure, with tiny tendrils extending off it. Text attached to the lymph nodes, which run all over the body, reads “Natural killer (NK) cells, stored in the lymph nodes, are sent out to kill diseased cells.” A microscopic image above the text shows the NK cell attaching to a diseased cell. Text attached to a lymph node in the man’s side reads “Macrophages are created where they are needed. They consume invaders and worn-out cells.”

GASTRIC ULCERS AND STRESSORS

Gastric ulcers have long been thought to be associated with stress, but the nature of this link has not always been clear. For many years, it was believed that stress alone caused gastric ulcers, but researchers then started to suspect other culprits. They found evidence that the bacterium H. pylori plays an important role. This does not mean that H. pylori is always to blame, however. Some people who carry the bacteria never get ulcers, while others develop ulcers in its absence. It seems that many factors influence the development of ulcers—among them, tobacco use, family history, and excess gastric acid (Fink, 2011).

CANCER AND STRESSORS

Cancer has also been associated with stress, both in terms of risk and development. Specifically, stress has been linked to the suppression of T lymphocytes and NK cells, which help monitor immune system reactions to the invasion of developing tumors. When a person is exposed to stressors, the body is less able to mount an effective immune response, which increases the risk of cancer (Reiche, Nunes, & Morimoto, 2004).

In the United States and other Western countries, breast cancer is the greatest cancer risk for women. Researchers have identified a number of stressors related to cancer (specifically breast and ovarian). Cancer often causes financial stress due to the high costs of treatment, the limited amount of sick leave one might have, and the physical pain associated with the illness (Andreotti, Root, Ahles, McEwen, & Compas, 2015).

Stress has been correlated with other types of cancer, though not always in the expected direction. One group of researchers examined the relationship between chronic daily stressors and the development of colorectal cancer using a prospective study in which nearly 12,000 Danes (who had never been diagnosed with colorectal cancer) were followed for 18 years (Nielsen et al., 2008). The researchers noted some surprising findings, particularly with respect to females. Women who reported higher levels of “stress intensity” and “daily stress” were less likely to develop colon cancer during the course of the study. In contrast, men with “high stress intensity” experienced higher levels of rectal cancer, although this association was not considered to be strong because only a small number actually developed this kind of cancer. The authors suggested that a variety of physiological, mental, and behavioral factors (for example, sex hormones, burnout, and increased alcohol intake) were involved in the relationship between high stress and lower rates of colon cancer in the women.

CONNECTIONS

In  Chapter 6 , we discussed the malleability of memory. Problems may arise when study participants are asked to remember events and illnesses from the past. Here, we describe a prospective study, which does not require participants to retrieve information from the distant past, thus reducing opportunities for error.

INFOGRAPHIC 12.3

Health Psychology

Health psychology is the study of the biological, psychological, and social factors that contribute to health and illness. Using the biopsychosocial perspective, health psychologists examine how a variety of factors, including diet, physical activity, and social relationships, impact our predisposition to illness. One of the primary goals is to increase positive health behaviors and decrease negative ones. Research in this field can benefit the health and well-being of individuals and the community at large through changes to public policy and health education.

Credits: Girl at desk, Prasit Photo/Getty Images. Man with dog, Antonio Gravante/Shutterstock.

There are two sections in the diagram, one on understanding stress, and the other on applied health psychology. Text under the title “Health Psychology” reads “Health psychology is the study of the biological, psychological, and social factors that contribute to health and illness. Using the biopsychosocial perspective, health psychologists examine how a variety of factors, including diet, physical activity, and social relationships, impact our predisposition to illness. One of the primary goals is to increase positive health behaviors and decrease negative ones. Research in this field can benefit the health and well-being of individuals and the community at large through changes to public policy and health education. The first section in the graphic is titled “Understanding Stress: The Biopsychosocial perspective.” Text under the title reads “Stress has been linked to a variety of negative health outcomes. The Biopsychosocial perspective helps us understand how the interaction between these factors contributes to our vulnerability. There are three factors shown: Biology, Psychology, and Social interaction. Arrows point out from both sides of each of these factors, showing less stress on the right side, and more stress on the left side. For Biology, text attached to the “more stress” arrow reads: “Viruses, bacteria, and other disease-causing organisms invade the body, triggering an immune response and putting a strain on the body’s resources.” Text attached to the “less stress” arrow reads “Exercise is one of the best ways to buffer against stress and its negative effects.” For Psychology, text attached to the “More stress” arrow reads “A perceived lack of control, even in mundane aspects of life, profoundly impacts our ability to manage stress.” Text attached to the “Less stress arrow reads “Research has shown that mindfulness meditation helps ease anxiety and depression.” For social interaction, text attached to the “More stress” arrow reads “Research has shown that feeling judged on one’s race, gender, income level and other factors has a negative impact on physical health and well-being.” Text attached to the “less stress” arrow reads “As a species, human beings are social and benefit from interaction with other humans and even animals”. The second section is titled “Health Psychology Applied”, and shows an image and text for each of the three factors. The subtitle for the “Biology” factor is “What’s in a color?” Below it shows an image of the color Pantone 448C, and that color on a pack of cigarettes. Text under the image reads “With public health in mind, Australia and the United Kingdom have begun requiring cigarette packs to be wrapped in “Opaque Couché” (Pantone 448C), deemed the ugliest color across the globe (BLAKEMORE, 2016, JUNE 9, PARA. 2). The packaging also features shocking images of smoking-related health consequences. Smoking rates in Australia fell after the new packaging was implemented and tobacco taxes were raised.” The subtitle for the “Psychology” factor reads “The power of thinking ‘Beyond the now”. Underneath the subtitle is a photograph of a girl sitting at a desk, and underneath that is text that reads as follows: “College students who were able to think about and plan for their futures showed an increase in positive health behaviors, such as exercise and conscientious eating habits.” The subtitle for the factor “Social Interaction” is “Animal therapy in crisis management”. Underneath the subtitle is a picture of a man in a wheelchair petting a dog, and underneath that is text that reads “Recognizing how animals can help people manage stress, professionals now use therapy dogs to facilitate coping.”

Why can’t researchers definitively characterize the link between cancer and stressors? Part of the problem is that studies frequently focus on stressors of different durations. Short- and long-term stressors have distinct effects on the immune system, and thus its ability to combat cancer (Dhabhar, 2014; Segerstrom & Miller, 2004). For shortlived stressors such as midterm exams, public speaking, and other activities lasting between 5 and 100 minutes, the body responds by increasing the number of NK cells and deploying other immune cells where needed. In other words, short-term stressors tend to augment immune functioning. The situation is quite different with long-term stressors such as military deployment or caring for someone with dementia, which are associated with decreases in NK cells. In order to appreciate the complex relationship between stress, immune function, and cancer, we must also consider biopsychosocial influences. Factors such as age, medical history, social support, and mental health can mediate the link between stressors and cancer (Reiche et al., 2004; Segerstrom & Miller, 2004).

Scott Olson/Getty Images.

Battling Stress

A group of Marines practice patrolling techniques as part of their combat training. Long-term stressors such as military deployment are associated with declines in activity of NK cells, which help the body fight infections (Dhabhar, 2014).

CARDIOVASCULAR DISEASE AND STRESSORS

The same is true for the relationship between stressors and cardiovascular disease. Dimsdale (2008) noted that over 40,000 citations popped up in a medical database when the search terms “stress” and “heart disease” were used. What constitutes a stressor in this context? Earthquakes, unhappy marriages, and caregiving burdens are just a few stressors associated with a variety of outcomes or vulnerabilities, ranging from abnormalities in heart function to sudden death. Earlier, we discussed socioeconomic status and stress; it turns out that both of those variables are factors in cardiovascular disease. Joseph and colleagues reported fivefold higher odds of experiencing “cardiometabolic events” (within 5 years) for people who became unemployed as a result of Hurricane Katrina, a devastating natural disaster that occurred in 2005 (Joseph, Matthews, & Myers, 2014). The faster people get support to decrease “socioeconomic disruptions” related to a disaster, the better their health outcomes.

Other stressors have also been linked to heart disease. “Social-evaluative threats,” or concerns about being judged by others (about physical appearance or behaviors in a social context, for example), are associated with increases in blood pressure and consequently an elevated risk of heart disease (Smith, Birmingham, & Uchino, 2012). One model suggests that increased job stress can put people at greater risk for developing coronary heart disease, particularly those who perceive a significant degree of job “strain” resulting from high demands, lack of control, and other factors (Ferris, Kline, & Bourdage, 2012).

The exact nature of the relationship between stressors, high blood pressure, and cardiovascular disease is not totally understood (Straub, 2014). However, we do know that an increase of fatty deposits, inflammation, and scar tissue within artery walls, that is, atherosclerosis, is a dangerous risk factor for stroke and heart disease (Go et al., 2013). With this type of damage, blood flow in an artery may become blocked or reduced. Researchers are not sure exactly how atherosclerosis starts, but one theory suggests that it begins with damage to the inner layer of the artery wall, which may be caused by elevated cholesterol and triglycerides, high blood pressure, and cigarette smoke (American Heart Association, 2014a). It is important to note that stressors cannot be shown to cause changes in cardiovascular health (Dimsdale, 2008). Although there is a clear correlation between biopsychosocial stressors and cardiovascular disease, we cannot say with certainty that these stressors are responsible (Ferris et al., 2012).

Stress and Substances

A great way to promote cardiovascular health and reduce stress is exercise. Both Christy and her husband, Ron, who also works in law enforcement, combat stress with regular workouts. They also unwind by sharing food and drink with friends. “A good way to deal with stress is laughter, or working out, getting together with your friends, enjoying a good meal,” says Christy, but she is careful to point out the importance of moderation. Christy and her husband do not drink excessively, but they have seen how the overindulgence of alcohol can ruin careers.

In  Chapter 4 , on consciousness, we described how people use alcohol and other drugs for recreational purposes, and how anesthesiologists rely on drugs to alleviate pain, block memories, and toy with various aspects of consciousness. But a discussion of drugs is also in order here, because many people mistakenly view substances as stress relievers. Psychologists explain this type of behavior with the self-medication hypothesis, which suggests that people turn to drugs and alcohol to reduce anxiety (Swendsen et al., 2000).

As you can see, stress often exerts its harmful effects indirectly (Cohen, Miller, & Rabin, 2001). When faced with stressors, we may sleep poorly, eat erratically, and perhaps abuse substances. These behavioral tendencies can lead to significant health problems (Benham, 2010; Ng & Jeffery, 2003).

Image Source/Alamy.

It’s Not Medicine

Some people turn to alcohol and other drugs for stress relief, but the self-medication approach is not effective. A better strategy might be jogging in the park, laughing with a friend, or doing some deep breathing exercises.

SMOKING AND STRESS

Smokers report that they smoke more cigarettes in response to stressors, as they believe it improves their mood. The association between lighting up and feeling good is one reason smokers have such a hard time quitting (Lerman & Audrain-McGovern, 2010). One study found that when participants were forced to abstain from smoking for some time (a half day, for example), their mood improved when they finally puffed on a cigarette. However, forgoing cigarettes was the only stressful condition of the study in which smoking heightened mood; the effect was not observed when participants were made to prepare for a public-speaking task, for example (Perkins, Karelitz, Conklin, Sayette, & Giedgowd, 2010). Yet, such findings are inconsistent with the self-reports of smokers, who claim that they smoke to feel better in a variety of stressful situations. And, due to the extreme health problems that smoking creates, smoking itself may eventually become the stressor.

How do we get people to kick a habit that is perceived as so pleasurable? One effective way is to meet them where they are, rather than taking a one-size-fits-all approach (Mahoney, 2010; Prochaska, Velicer, Prochaska, Delucchi, & Hall, 2006). In other words, we should recognize that not all smokers need the same type of help. Some need assistance with smoking only; others engage in additional risky behaviors, like eating high-fat diets or getting too much sun. Yet, even if we tailor interventions to address the needs of the individual, the road to recovery may be bumpy. Remember that nicotine is extremely addictive. Repeated use can lead to tolerance; the more you use a drug, the more you need to achieve the same effect.

CONNECTIONS

In  Chapter 4 , we discussed the concept of tolerance. When we use drugs, such as nicotine, they alter the chemistry of the brain and body. Over time, the body adapts to the drug and therefore needs more and more of it to create the original effect.

ALCOHOL AND STRESS

Much the same could be said for alcohol, another drug frequently used to “take the edge off,” or counteract, the unpleasant feelings associated with stress. Perhaps you know someone who “needs” a drink to relax after a rough day. Teenagers, in particular, appear to rely on alcohol to cope with daily hassles (Bailey & Covell, 2011). Adolescents frequently face disagreements with family members, teachers, and peers. They may worry about how they look and whether they are succeeding in school. We need to help adolescents find new and more “healthy” ways to handle these hassles. This means providing more support in schools, and perhaps educating teachers and counselors about the tendency to self-medicate with drugs and alcohol. Researchers have found that people who start using alcohol early in life and have a “greater number of stressful life events demonstrated the highest consumption of alcohol in early adulthood” (Stanger, Abaied, & Wagner, 2016, p. 483).

Later, we will discuss some positive coping strategies for teens and adults alike, but first let’s see how some people seem to thrive under stress. Get ready to meet Kehlen Kirby, our next first responder.

ADRENALINE JUNKIES

Tetra Images/Superstock.

Kehlen Kirby sees more pain and suffering in one month than most people do in a lifetime. Working as an emergency medical services (EMS) provider in Pueblo, Colorado, this young man has witnessed the highest highs and lowest lows of human experience. He has rescued people from flaming car wrecks, treated teenage gang members for stab and gunshot wounds, and watched chain-smokers who are dying from emphysema beg for cigarettes en route to the hospital. In between the sadness and suffering, there are also stories of hope and inspiration, as when Kehlen and his colleagues delivered a baby on the shoulder of U.S. Route 50, and the mother went from a state of screaming hysteria to smiling, laughing bliss.

The reward of alleviating human suffering is “incredible,” according to Kehlen. Imagine walking into the home of a diabetic who is lying on the floor, unconscious and surrounded by trembling family members. You insert an IV line into the patient’s vein and deliver D50, a dextrose solution that increases blood sugar. In a few moments, the person is awake as if nothing happened. The family is ecstatic; you have saved their loved one from potential brain damage or death. “People that like to do selfless acts, I think, are made for this job,” Kehlen says. And for those who enjoy a good challenge, both physical and mental, an EMS career will not disappoint. Try working for 24 hours in a row, making life-and-death decisions, hoisting heavy bodies onto stretchers, and crouching over patients until your joints burn.

But there appears to be something else drawing people into the EMS profession. You might call it the “adrenaline junkie” factor. Ever since Kehlen was a small boy, he enjoyed a certain amount of risk taking. He was the kid who fearlessly scaled the monkey bars and leaped off the jungle gym, and many of his colleagues claim they were the same way. “All of us probably thought we were 10 feet tall and made of steel,” Kehlen says, careful to note that “daring” is not the same as “reckless.” One must be calculating when it comes to determining what risks are worth taking.

The adrenaline junkie quality is also apparent in some police officers, according to Christy. An officer patrolling a city beat probably experiences the so-called adrenaline rush at least a few times per week. “When a hot call comes in, anyone worth their salt wants to go,” Christy explains (“hot call” meaning anything full of excitement and drama, like a robbery in progress).

Leslie Nazario/Portraits by Leslie.

Life Saver

Kehlen Kirby has one of the most stressful jobs imaginable— providing emergency medical services to people injured in car accidents, fires, and other traumatic incidents. The constant exposure to pain and suffering helps Kehlen maintain perspective on the hassles of daily life; he doesn’t sweat the small stuff.

Is there really some common adrenaline junkie tendency among police officers, EMS providers, and other first responders? That remains an open question.Arousal theory tells us that humans seek an optimal level of arousal, and what is optimal differs from person to person. We also know that first responders are frequently exposed to highly stressful events (Anderson, Litzenberger, & Plecas, 2002; Gayton & Lovell, 2012). Could it be that people like Kehlen and Christy are drawn to these careers because they satisfy a need for arousal? Perhaps, but even adrenaline junkies have their limits. When stress is constant, the body and mind begin to suffer. 

CONNECTIONS

In  Chapter 9 , we introduced arousal theory, which suggests behaviors can arise out of the need for stimulation or arousal. Here, we point out that some people seek stressors in order to maintain a satisfying level of arousal.

Too Much Cortisol

LO 8 List some consequences of prolonged exposure to the stress hormone cortisol.

Earlier, we discussed the stress hormone cortisol, which plays an important role in mobilizing the body to react to threats and other stressful situations. Cortisol is useful if you are responding to immediate danger, like a raging fire or ruthless assailant. However, you don’t want cortisol levels to remain high for long. Both body and brain are impacted when the cortisol system flips into overdrive.

CORTISOL AND KIDS

The negative effects of stress are apparent very early in life. Infants born to mothers subjected to natural disasters, trauma, and other extreme stressors are more likely to be born prematurely, have low birth weights, exhibit behavioral difficulties, and perhaps even show problems with cognitive development (Davis & Sandman, 2010; Tollenaar, Beijers, Jansen, Riksen-Walraven, & De Weerth, 2011). Prenatal stressors have also been associated with fussing and crying, but this link might be indirect (Field & Diego, 2008); such temperamental difficulties could be due to preterm birth (Baibazarova et al., 2013).

Now consider the types of stressors some preschool children confront every day. Research shows that conflicts at home can increase cortisol levels in children (Slatcher & Robles, 2012). Verbal exchanges such as the child exclaiming, “No! I don’t want to!” and parents saying, “You are going to shut your mouth and be quiet!” are exactly the types of conflicts associated with increased cortisol levels. Cortisol activity may help explain why exposure to conflict during childhood seems to pave the way for health problems (Slatcher & Robles, 2012).

There is little doubt that cortisol plays a role in early development. But how does this stress hormone affect teens?

THINK IT THROUGH

Waking Up Is Hard to Do

Think back to your days in high school. Like many of today’s teens, you probably balanced multiple responsibilities—schoolwork, extracurricular activities, and perhaps a part-time job. After doing homework late into the night, you drifted off to sleep, only to have your slumber rudely cut short by an annoying alarm clock. You scrambled to get to school before the first bell rang (usually well before 8:00 A.M.), and slogged through your morning classes feeling tired and exhausted because you simply did not get enough sleep.

LATER SCHOOL START TIMES ARE LINKED TO IMPROVED ACADEMIC AND HEALTH OUTCOMES FOR TEENS.

Many U.S. high school students deal with this type of scenario on a regular basis, and their sleep deprivation may have serious consequences. Evidence suggests that inadequate sleep and other sleep issues lead to heightened levels of cortisol, which could play a role in “academic, behavioral and health problems” (Mrug, Tyson, Turan, & Granger, 2016, p. 95). For example, teens who get less than 8 hours of sleep are more likely to experience symptoms of depression, use caffeine, and have an elevated risk for substance use (Wahlstrom et al., 2014).

One way to help teenagers get more sleep is to push back school start times. According to a study by researchers at the University of Minnesota, more than 60% of high school students would be able to get 8 hours of sleep if classes started after 8:30 A.M. Such an intervention could reduce absenteeism and tardiness and potentially improve grades and performance on standardized tests. It may even help young people stay safe; the researchers also found there was a 70% decrease in the number of car accidents among drivers ages 16 to 18 when school start times changed from 7:35 A.M. to 8:55 A.M. (Wahlstrom et al., 2014). Evaluating this evidence, the American Academy of Pediatrics “urges middle and high schools to aim for start times that allow students to receive 8.5–9.5 hours of sleep at night” (American Academy of Pediatrics, 2014, August 25, para. 10).

With all of this research pointing to the benefits of a later start time, why haven't more school districts implemented this change? Many are resistant to changing start times because it may complicate school bus transportation, parents’ work schedules, child care, and school sports (Wahlstrom et al., 2014). Do you think the benefits of later start times outweigh the costs? .

Alejandro Rivera/Getty Images.

Performance Anxiety

Heightened cortisol levels can help or hinder a person studying for a math test. For people with “higher working memory” and low math anxiety, cortisol seems to boost performance, but it has the opposite effect when math anxiety is high (Mattarella-Micke, Mateo, Kozak, Foster, & Beilock, 2011).

Now that we have explored how excess cortisol impacts children and teens, let’s see how it might affect the functioning of adults. We’ll use a law enforcement scenario as our example.

CORTISOL ON THE JOB

How might heightened cortisol levels impact the behaviors of police officers making on-the-spot safety decisions? In one study, researchers had police officers participate in a realistic simulation of being targeted by shooters. Not only did the officers’ cortisol levels rise, but the functioning of their working memory decreased (Taverniers, Smeets, Van Ruysseveldt, Syroit, & von Grumbkow, 2011). Can you imagine the implications of being in a dangerous situation with impaired working memory? Think of the last time you were really afraid, and how difficult it was to think clearly. Your working memory was probably compromised.

CONNECTIONS

In  Chapter 6 , we presented the concept of working memory, which refers to how we actively maintain and manipulate information in short-term memory. Here, we see how these activities can be impacted by stressful situations.

Other research suggests that heightened cortisol levels may decrease errors in decision making. When police officers had to make threat-related decisions in a video simulation, they were better able to discern whether an individual was armed when their cortisol levels were high. But this accuracy increased when the officer faced a simulation involving a Black suspect, and decreased when the suspect was White. This finding was the same for the White officers and minority officers participating in the study. The researchers concluded that higher cortisol levels, which were caused by the stressful situation, resulted in “heightened vigilance for danger” (Akinola & Mendes, 2012, p. 172). Apparently, the perceived threat of Black men was greater, which is consistent with what social psychologists have learned about the conscious and unconscious reactions many people have to racial minorities ( Chapter 15 ). A more recent meta-analysis of studies concluded that participants engaged in shooting tasks were “quicker to shoot armed Black targets, slower to not shoot unarmed Black targets, and were more likely to have a liberal shooting threshold for Black targets” (Mekawi & Bresin, 2015, p. 128).

You Asked, Christy Answers

 

 

PSYCHONEUROIMMUNOLOGY

We have now discussed some of the effects of short- and long-term stressors. You know that a spurt of cortisol steps up immunity and prepares the body to confront a threat. You also know that if cortisol levels remain high for prolonged periods (as occurs with chronic stressors), the immune system may not function at an optimal level. We discussed how this affects one’s risk for developing gastric ulcers, cancer, and heart disease, but the list of negative health effects is much longer. According to a meta-analysis of over 300 studies, chronic stressors were found to be associated with problematic immune system responses, which may increase the risk for various illnesses involving inflammation, including asthma, allergies, multiple sclerosis, and rheumatoid arthritis (Segerstrom & Miller, 2004). The exact nature of these relationships has yet to be determined, but researchers are working hard to uncover them, especially for people who are aging and have vulnerable immune systems (Cohen et al., 2001). It is an exciting time for those who specialize in the field of  psychoneuroimmunology  (SI-koh-NUR-oh-IM-mu-NOL-oh-gee), which examines the relationships among psychological factors (such as coping, emotions, and beliefs), the nervous system, and the functioning of the immune system (Slavich, 2016).

The field of health psychology, which draws on the biopsychosocial model and psychoneuroimmunology, has shed light on the complex relationship between stress and health (Havelka, Lučanin, & Lučanin, 2009). Now that we understand how profoundly stressors can impact physical well-being, let’s explore how different people tolerate and respond to stress.