PSYCH 634 Week 3 Hormones, Stress and the Endocrine System Example

Twelve-Hour Shifts on the 911 Console: The Stress Hormone System, Wear and Tear and One Dispatcher's Sleepless Nights

[Student Name]

University of Phoenix

PSYCH/634: Biological Basis of Behavior

Week 3 Assignment

[Instructor Name]

[Date]

The dispatcher, the sleep center and the work schedule are composites written for a model paper; research findings come from the sources listed.

The endocrine system uses hormones to coordinate the body over seconds, hours and years. Its stress response helps people meet challenges, but repeated activation can harm health and sleep. This paper explains that system through a patient I met at the sleep center where I work.

The Patient

Denise Harlan is forty-four and has worked for eleven years as a 911 dispatcher in Pima County, Arizona. She works rotating twelve-hour shifts, two days, two nights and three days off, answering calls about car crashes, overdoses, domestic violence and fires. For two years she has slept poorly. After night shifts she lies awake replaying calls; after day shifts she wakes at three in the morning with her heart pounding. She has gained twenty pounds and catches every cold. Her physician referred her for a sleep evaluation to rule out a sleep disorder.

How Hormones Carry Signals

Hormones are chemical messengers released by glands into the blood, reaching cells throughout the body that carry matching receptors. Unlike neurotransmitters, which act across a synapse in milliseconds, hormones act over seconds to days. Sitting just above the roof of the mouth, the hypothalamus acts as the bridge between nerves and glands: it gives orders to the pituitary, and the pituitary passes them on to the thyroid, the adrenals and the reproductive glands.

Two Arms of the Stress Response

When Denise takes a call about a child who is not breathing, two systems respond. The first is fast. The sympathetic nervous system sends signals to the adrenal medulla, the inner part of the adrenal glands, which releases adrenaline and noradrenaline within seconds. Heart rate and blood pressure rise, breathing quickens and stored energy is released into the blood.

The second arm is slower. The hypothalamus releases corticotropin-releasing hormone, which signals the pituitary to release adrenocorticotropic hormone into the blood. That hormone reaches the adrenal cortex, the outer layer, which releases cortisol. Cortisol peaks about twenty to thirty minutes after a stressor begins. It mobilizes energy, adjusts immune activity and affects the brain, including memory for emotional events. Cortisol also feeds back to the hypothalamus and pituitary, shutting down further release once the challenge passes.

Protection and Damage

McEwen (1998) made the point that the chemicals of the stress response guard us over minutes and hours but injure us over months and years if they fire too often, linger after the threat or fall out of step with one another. His term allostasis captures how the body stays steady by shifting gears, such as speeding the heart for a sprint; allostatic load is the bill that comes due when those shifts happen too often or last too long. Patterns that raise load include frequent stress, failure to adapt to repeated stressors, prolonged responses that do not end and inadequate responses that leave other systems overactive. McEwen linked allostatic load to high blood pressure, abdominal fat, impaired immunity and changes in brain regions involved in memory and emotion.

Denise's work fits several patterns: repeated stressors several times per shift, little time to recover between calls and nights spent replaying events, which prolongs activation after the shift ends.

Which Stressors Raise Cortisol Most?

Dickerson and Kemeny (2004) combined 208 laboratory studies of acute stress and cortisol. Cortisol rose most for tasks that were uncontrollable and that carried social-evaluative threat, meaning that others could judge the participant's performance. Tasks with both features produced the largest and longest-lasting responses. Simple demanding tasks without these features produced smaller changes.

Dispatch work combines both features. Dispatchers cannot control what happens at the scene, and calls are recorded and reviewed, with supervisors and sometimes the public judging their decisions.

Every call on the console is uncontrollable and recorded, the two features that most reliably push cortisol up.

What Happens With Chronic Stress

One might expect chronic stress to keep cortisol high. Miller et al. (2007) examined this question in a meta-analysis of studies comparing people under chronic stress with controls. Cortisol patterns depended on the nature of the stressor and its timing. Soon after a stressor began, cortisol was often elevated, but as time passed, levels tended to fall below normal in the morning, and the daily rhythm flattened. Stressors involving threat to physical integrity, trauma and uncontrollability produced flatter patterns, and the persistence of the stress and the person's emotional response also mattered.

Normally cortisol peaks shortly after waking and falls through the day, reaching its lowest point around midnight. A flattened rhythm, with lower morning levels and higher evening levels, is associated with fatigue, poor sleep and health problems. Rotating shift work also disrupts this rhythm directly, since cortisol timing is tied to the body's circadian clock.

Stress Hormones and Sleep

Sleep and the stress system influence each other. Sleep normally begins as cortisol reaches its low point, and activation of the stress response at bedtime makes falling asleep harder. Denise's racing heart at three in the morning suggests sympathetic activation during the night, and replaying calls keeps the system engaged. Poor sleep, in turn, raises evening cortisol and sympathetic activity the next day, creating a cycle.

Metabolism and Immunity

Two of Denise's other complaints fit the biology. Cortisol helps raise blood sugar and, when elevated at the wrong times, promotes fat storage around the abdomen and increases appetite for calorie-dense food. Disrupted sleep adds to these effects. Cortisol also adjusts immune function; over time, dysregulated stress hormones are associated with weaker defenses against common infections, which may explain why she catches every cold.

Why Some Dispatchers Cope Better

Not every dispatcher develops insomnia. People differ in how strongly and how long their stress systems respond, shaped by genetics, early experience, health and the meaning they give to events. Social support also matters: dispatchers who can talk through a hard call with a partner or supervisor may shut down the response sooner. Denise told me her center lost two experienced colleagues last year, leaving her as the most senior person on most night shifts and the one others turn to after bad calls, with no one to turn to herself.

What the Sleep Study Found

Denise's overnight study showed no apnea, but long periods awake after initial sleep onset and fragmented sleep. Her sleep physician diagnosed chronic insomnia related to shift work and stress.

What Helps

Recommendations combined behavioral and organizational steps. Cognitive behavioral therapy for insomnia, a first-line treatment, addresses racing thoughts and sleep habits. A brief wind-down routine after shifts and a consistent sleep window on days off can stabilize her rhythm. Her dispatch center offers peer support and critical incident debriefing, which may reduce prolonged activation after difficult calls. And Denise asked her supervisor about a schedule that rotates forward, from days to nights, rather than backward, which is easier on circadian rhythms.

Conclusion

Denise's insomnia, weight gain and frequent illness reflect a stress system doing its job too often, without enough recovery. Hormones that help her respond to emergencies, when activated repeatedly by uncontrollable and evaluated calls on a rotating schedule, add up to allostatic load. Understanding the biology points to remedies that restore recovery, not only to sleep medication.

References

Dickerson, S. S., & Kemeny, M. E. (2004). Acute stressors and cortisol responses: A theoretical integration and synthesis of laboratory research. Psychological Bulletin, 130(3), 355-391. https://doi.org/10.1037/0033-2909.130.3.355

McEwen, B. S. (1998). Protective and damaging effects of stress mediators. New England Journal of Medicine, 338(3), 171-179. https://doi.org/10.1056/NEJM199801153380307

Miller, G. E., Chen, E., & Zhou, E. S. (2007). If it goes up, must it come down? Chronic stress and the hypothalamic-pituitary-adrenocortical axis in humans. Psychological Bulletin, 133(1), 25-45. https://doi.org/10.1037/0033-2909.133.1.25