Think about the last time you encountered a spider — you might have initially jumped, felt your hair stand up on your arms and legs, or run away when you saw it. Encounters with a spider, being mugged in a dark alley, giving a public speech or getting into a car accident are all universal in their ability to elicit the body’s “fight-or-flight” response, which is an important survival mechanism that produces a series of physiological changes that prepare our bodies to respond by either standing our ground and fighting off the threat or fleeing from a potentially dangerous situation.
Our reaction to seeing a spider is a prime example of the body’s fight-or-flight response in action. The body’s stress response system — the hypothalamic-pituitary-adrenal (HPA) axis — as its name suggests, consists of the hypothalamus, pituitary gland and adrenal glands. The function of the HPA axis is to provide the body with a quick supply of energy to fuel the muscles and allow a person to escape from a dangerous situation. When a potential threat such as a spider is detected by the amygdala (an area of the brain responsible for emotional processing), a distress signal is sent to the hypothalamus, which sets off an alarm system in the body and activates the fight-or-flight response.
The hypothalamus prompts the adrenal glands to release chemical hormones, primarily adrenaline (i.e., epinephrine), noradrenalin (i.e., norepinephrine) and cortisol (i.e., the primary stress hormone), which play a role in keeping us alert, making our blood pump faster and harder, and providing our bodies with adequate energy supplies to fight or flee from a threat. Adrenaline and norepinephrine are chiefly responsible for producing the immediate reactions when we feel stressed — our heart rate increases, blood pressure spikes, muscles tense up, pupils dilate and breathing becomes faster.
These hormones also play an essential role in boosting alertness and producing a surge of energy by triggering the release of extra glucose (i.e., blood sugar) by the liver and fats from temporary storage sites in the body. After the initial surges of adrenaline and noradrenalin subside, the release of corticotrophin-releasing hormone (CRH) by the hypothalamus triggers the release of adrenocorticotropic hormone (ACTH) by the pituitary gland, which prompts the adrenal glands to continue to produce cortisol until a threat has passed.
How does stress impact our physical health?
Chronic stress is a major problem in the United States — almost one-third of all American adults report that stress had a “strong” to “very strong” impact on their physical and mental health, while more than 40 percent of adults reported lying awake at night due to stress. Although stress is beneficial in short-bursts (e.g., during an important exam or meeting a deadline at work), such chronic stress can have a major consequences on a person’s physical and mental health, contributing to illnesses such as heart disease, obesity, Type 2 diabetes, anxiety, insomnia, depression, and muscle tension and pain.
The body’s production of cortisol, adrenaline and noradrenalin during the stress response is helpful for providing us with the immediate energy we need to escape from danger or to protect ourselves from a threat. However, this temporary surplus of energy comes at the expense of other important body processes, such as digestion, growth, reproduction and the immune system, which are temporarily inhibited during the stress response as they are not necessary for immediate survival, said Dina Aronson, M.S., a registered dietitian and president of Wellness & Technology Unite.
How does chronic stress impact the brain?
Researchers have found that elevated cortisol levels can contribute to atrophy — or brain shrinkage — specifically in areas of the brain like the hippocampus, where memories are processed and stored. Studies also demonstrate that glucocorticoids such as cortisol play a major role in memory formation. As such, prolonged stress can have long-lasting effects on memory, learning, attention and mood, and produce cognitive difficulties similar to those seen in the very elderly; children who are chronically stressed may begin exhibiting problems around middle age, said Sudhir Kumar, M.D., a senior consultant and neurologist.
Even low levels of chronic stress can keep the HPA axis activated, which can lead to too much cortisol being produced in the body. Some of the most substantial consequences of excess cortisol include the consequences on a person’s brain structure, leading to problems with memory, learning and mental health. As a result of excess cortisol, people who are chronically stressed may feel constantly run-down, overwhelmed, anxious and worried.
The repeated release of excess cortisol produced from chronic stress can also be disruptive to the normal levels of neurotransmitters and other hormones in the body. For example, the dysregulation of the HPA axis can contribute to reduced levels of serotonin, a neurotransmitter that is responsible for regulating moods, appetite and sleep, and dopamine, a brain chemical responsible for reward and pleasure.
Although many factors play a role in our susceptibility for mental illness, numerous studies indicate that stress is a crucial environmental factor in our susceptibility for certain types of mental disorders and other cognitive problems. Researchers suggest that chronic stress can play a role in the initiation of mental health problems, especially depression and anxiety disorders, when there is too much cortisol in the body; researchers have also found that low cortisol levels are associated with post-traumatic stress disorder (PTSD).
Numerous factors contribute to our ability to deal with everyday stress. For example, those who exercise regularly, eat healthily and have a strong supportive network of family members and friends may be less vulnerable to the negative consequences of stress. The Sovereign Health Group recognizes the physical and mental health consequences that chronic stress has on the lives of our patients. To combat chronic stress, our patients are offered a holistic array of behavioral health treatment services, including tools to help patients with substance abuse, mental illness and co-occurring disorders effectively reduce their stress. To find out more about Sovereign Health’s treatment programs, please contact our 24/7 helpline to speak to a member of our team.
About the author
Amanda Habermann is a writer for the Sovereign Health Group. A graduate of California Lutheran University, she received her M.S. in clinical psychology with an emphasis in psychiatric rehabilitation. She brings to the team her background in research, testing and assessment, diagnosis and recovery techniques. For more information and other inquiries about this article, contact the author at firstname.lastname@example.org.