Science 101: Stress & Mastering Your Body’s Response

Feeling stressed? Well, you’re not alone! Stress is like that uninvited guest who always crashes the party; persistent, demanding, and seemingly never willing to leave. Whether it’s a looming deadline, a tangled web of responsibilities, or the daily hustle and bustle of life, stress has a way of creeping into our lives like a stealthy ninja, ready to strike at any moment. Stress is a pervasive part of daily life, leaving many of us in a constant state of “fight or flight.” In this article, we’re going to unravel the science behind stress, discover its surprising benefits (yes, you read that right!), and equip you with a stress-busting arsenal to kick that unwelcome intruder to the curb. Let’s dive into the wild world of stress and learn how to turn it from a villain to a mighty ally in our quest for balance and well-being.


The Biology of Stress: Understanding Your Body’s Reaction


In order to understand how stress happens, we must first understand some of the body’s most basic systems.


Central Nervous System (CNS)


The CNS consists of the brain and spinal cord. It plays a vital role in maintaining homeostasis or balance, allowing individuals to interact with their environments and enabling complex cognitive processes to occur. This system works in conjunction with the peripheral nervous system.


Peripheral Nervous System (PNS)


The PNS comprises the nerves that connect the CNS to the rest of the body. This facilitates communication between the brain and various organs, muscles, and tissues throughout the body.


Autonomic Nervous System (ANS)


A branch of the peripheral nervous system that regulates and controls involuntary bodily functions such as heart rate, digestion, respiratory rate, blood pressure, body temperature, and glandular secretion. [1] The ANS consists of two main branches which work in tandem to maintain the overall balance and harmony of the body’s physiological processes.  

  1. Sympathetic Nervous System: prepares the body for “fight or flight” in response to stressful or dangerous situations. It increases heart rate, dilates pupils, redirects blood flow to vital organs, and prepares the body for quick action.
  2. Parasympathetic Nervous System: promotes relaxation, rest, and digestion. It slows the heart rate, constricts pupils, stimulates digestion, and conserves energy.


Only one of these systems can be active at any given time and if one is engaged more than another, the body is not in balance. Likewise, when the physiologic response to stress is maintained over time it can be harmful for our health and wellness. [1]


Stress and Its Impact: Looking at the Body and Mind


During a fight or flight stress response, our sympathetic nervous system is triggered, kicking off up to 1400 chemical, physical, and psychological changes to help the body protect itself. [2] Our muscles contract, and our blood pressure, heart rate, and respiration all increase. Stress hormones like cortisol, adrenaline, and noradrenaline are released. All nonessential processes such as digestion, reproduction, and wound repair slow down or come to a halt. In this state, the mind remains highly alert and thoughts can become obsessive, repetitive, and tunnel-like until the body feels safe again. [2]


After periods of stress, and ONLY once the brain perceives that the body is in a safe environment, the parasympathetic nervous system takes over to help restore calm and bring the body back into balance. [2]


Because the sympathetic nervous system triggers when we feel real OR “imagined” danger or stress – we experience the same reaction whether we are running from an angry bear or worried about missing an airplane flight – in today’s society, our stress response is almost constantly activated. Thanks to “imagined” stress – anxiety about work, politics, family, technology, etc. our sympathetic nervous system is often running on overdrive. Often our minds rarely feel safe enough to trigger the parasympathetic nervous system, thereby creating an imbalance in our ANS. It is likely that this imbalance is at the root of stress-related health symptoms and ailments. [2] 


Understanding Cortisol, “The Stress Hormone”


Cortisol is a hormone produced by the adrenal glands – located on top of the kidneys – which plays a crucial role in the body’s response to stress as well as regulating key physiological processes like metabolism and blood pressure modulation  When the body feels physical, emotional, or psychological stress, cortisol is released to prepare the body for a “fight or flight” response by increasing heart rate, blood pressure, and energy availability. [3]


Cortisol is essential for normal physiological functioning and it is normal for cortisol levels to fluctuate throughout the day. However, chronic or prolonged exposure to high levels of cortisol due to chronic stress can have negative health effects including disrupted sleep patterns, impaired immune function, increased risk of cardiovascular disease, weight gain, mood disturbances, and impaired cognitive function. [3]


In addition to stress, cortisol also helps to regulate the following:


Metabolism Regulation


Cortisol influences the metabolism of carbohydrates, fats, and proteins. It promotes the breakdown of stored glycogen into glucose, raising blood sugar levels to provide an immediate energy source during stress or fasting. [3]


Immune System Modulation


Cortisol has anti-inflammatory properties and can suppress the immune system. This effect helps regulate the immune response and prevent excessive inflammation in the body. [3]


Blood Pressure Regulation


Cortisol works with other hormones to regulate blood pressure. It helps maintain vascular tone and responsiveness to other vasoconstrictors, which affects blood pressure levels. [3]


Sleep-Wake Cycle


Cortisol follows a diurnal rhythm, with higher levels in the morning and lower levels at night. It helps promote wakefulness and alertness during the day and gradually decreases in the evening to support restful sleep. [3]


Warning Signs: Recognizing When Stress is Taking a Toll


Today, 75-90% of doctor visits are attributed to stress-related symptoms. [4] Stress can have widespread impacts on our bodies, affecting us physically, mentally, emotionally, and behaviorally. An overactive sympathetic nervous system can trigger increased cortisol output thereby exposing bodily tissues to excessive amounts of this hormone. Over time this repeated exposure may lead to tissue damage and negative health effects from the increased pressure placed on the body. [10] Here are some common examples of how stress impacts our bodies:


  1. Cardiovascular Issues: Chronic stress can lead to high blood pressure and heart disease, as well as an increased risk of heart attacks and strokes. Overproduction of stress hormones, such as cortisol, can contribute to the development of these conditions. [5]
  2. Weakened Immune System: Prolonged stress can weaken your immune system, making you more susceptible to infections, illnesses, and slower healing. It can also exacerbate autoimmune disorders. [7]
  3. Digestive Problems: Stress can disrupt the normal functioning of your digestive system, leading to issues like stomach aches, indigestion, diarrhea, or constipation. It may also contribute to the development of conditions such as irritable bowel syndrome (IBS). [6] 
  4. Mental Health Disorders: Stress is closely linked to mental health problems such as anxiety disorders and depression. Prolonged stress can worsen these conditions or increase the likelihood of developing them. [6]
  5. Sleep Disturbances: Stress often causes sleep disturbances such as insomnia or disrupted sleep patterns. Lack of sleep, in turn, can further contribute to physical and mental health problems. [6]
  6. Weight Gain and Eating Disorders: Stress can trigger emotional eating or cravings for unhealthy foods, leading to weight gain and an increased risk of developing eating disorders like binge eating or bulimia. [6]
  7. Muscle Tension and Pain: Stress can result in muscle tension, leading to headaches, backaches, and general muscle pain. It can also exacerbate existing chronic pain conditions, such as migraines or fibromyalgia. [6]
  8. Impaired Cognitive Function: Chronic stress can impair cognitive function, affecting memory, concentration, decision-making, and overall mental performance. It may also contribute to brain shrinkage over time. [6]
  9. Sexual Dysfunction: Stress can affect sexual desire and performance, leading to problems such as erectile dysfunction or a decrease in libido. [6]
  10. Skin Problems: Stress can aggravate skin conditions like acne, eczema, psoriasis, and hives. It may also delay the healing process of wounds and increase the appearance of wrinkles. [6]


Strategies for Better Stress Management


There are many effective coping techniques that can help manage and reduce stress and improve overall well-being. When we think about stress management let’s think about the Four A’s: avoid, alter, adapt, and accept. Here are some commonly recommended coping strategies including the Four A’s:


  1. Avoid Unnecessary Stress:  Learn to say no when you feel overwhelmed or overburdened. Establishing boundaries and prioritizing self-care is crucial for managing stress effectively. [9]
  2. Alter the situation: Be willing to compromise, create a balanced schedule, and surround yourself with people who make you feel relaxed and comfortable.
  3. Adapt to the stressor: Practice reframing problems with a positive mindset, adjusting your standards to be more realistic, and looking at the big picture. Build resilience to stress through solid wellness habits and routines by eating a balanced diet, getting enough sleep, and avoiding excessive consumption of caffeine, alcohol, and nicotine.
  4. Accept the things you can’t change: Look for the upside in stressful or upsetting situations. Challenge negative or distorted thoughts by reframing them and focusing on a positive outlook. [9] Limit or avoid “doom scrolling” or excessive consumption of negative news to reduce feelings of helplessness and overwhelm.
  5. Relaxation: Practice relaxation techniques such as deep breathing exercises, progressive muscle relaxation, guided imagery, or meditation. These techniques can help calm the mind and body, reducing stress levels. [8]
  6. Hobbies and Leisure Activities: Engage in activities you enjoy, such as hobbies, sports, reading, listening to music, or engaging in creative outlets. These activities can serve as distractions, promote relaxation, and provide a sense of accomplishment.
  7. Self-Care: Dedicate time for self-care activities that promote relaxation and rejuvenation, such as taking a bath, journaling, practicing mindfulness, getting a massage, or engaging in activities that bring you joy and fulfillment. [9]
  8. Seek Professional Help: If stress becomes overwhelming or persists despite your efforts, consider seeking professional help. A therapist or counselor can provide guidance, support, and additional coping strategies tailored to your specific needs. [9]


Remember that everyone’s response to stress is unique, so it’s important to find coping techniques that work best for you. Experiment with different approaches and be patient with yourself as you develop a stress reduction routine. For more tips on stress management be sure to check out our Stress Primer!


Destress with EQIncorporating multiple stress management techniques can significantly enhance our resilience to stress. We’ve all heard the phrase, “You can’t pour from an empty cup”, emphasizing the importance of self-care. When we’ve taken the time to care for our nervous system, we become better equipped to handle the stressors that come our way. 


Stress is an inevitable part of life and our bodies are designed to respond to it in order to protect us from danger. However, our modern world has made it difficult to differentiate between real threats versus perceived ones, which can keep the stress response active in our bodies for extended periods. Chronically high levels of stress can cause a multitude of health issues including heart disease and a weakened immune system. Fortunately, we can take action by practicing different stress management techniques to calm down our bodies and elicit the relaxation response. By actively engaging in stress management practices, you can cultivate a healthier relationship with stress.



[1] Understanding the stress response. Harvard Health. Published March 1, 2011. Accessed June 14, 2023.

[2] Parasympathetic vs Sympathetic Nervous System – Difference and Comparison | Diffen. Accessed June 14, 2023.

[3] Stress effects on the body. Accessed June 14, 2023.

[4] Marksberry K. America’s #1 Health Problem. The American Institute of Stress. Accessed June 15, 2023.

[5] Stress and Heart Health. Accessed June 14, 2023.

[6] Marksberry K. Stress Effects. The American Institute of Stress. Accessed June 14, 2023.

[7] Dragoş D, Tănăsescu M. The effect of stress on the defense systems. J Med Life. 2010;3(1):10-18.

[8] MayoClinicHealthSystem. Five tips to manage your stress. Mayo Clinic Health System. Accessed June 15, 2023.

[9] Tips for Coping with Stress|Publications|Violence Prevention|Injury Center|CDC. Published July 18, 2022. Accessed June 15, 2023.

[10] O’Connor DB, Thayer JF, Vedhara K. Stress and Health: A Review of Psychobiological Processes. Annual Review of Psychology. 2021;72(1):663-688.