How Does Stress Affect the Body?

Your head is pounding. You can’t sleep. You’re forgetful, anxious and just plain irritable. It’s a familiar scenario – one that millions of Americans experience daily. Welcome to stress overload.

Stress has been with us since the beginning of time. This is not necessarily a bad thing. Some types of stress can generate the impetus necessary to convert thought into action, whether that action is planting a garden, meeting a deadline or escaping from a fire or flood. In fact, stress has been the force behind much of our progress through the ages. But when stress becomes a frequent occurrence, our health, goals, and relationships can all suffer. That’s because stress can affect our moods and our ability to think clearly. It can also weaken our immune system and make us more susceptible to getting sick.

What is stress?

At its core, stress is essential to our survival. In fact, Hans Selye, MD, Ph.D., a Canadian endocrinologist who coined the term “stress” in 1936, noted that “To be totally without stress is to be dead”. (1)(2) When faced with danger, whether real or perceived, we experience a built-in fight or flight response. This underlying stress response system involves the hypothalamus, pituitary, adrenal (HPA)-axis. Once activated, the HPA-axis instantly puts us on alert and primes the body to either flee the situation or defend against it.

man sitting at a desk looking at his laptop

The HPA-axis is responsible for your “fight or flight” response to stressful events.

This response begins in the hypothalamus, a tiny cluster of cells at the base of the brain that controls things like your body temperature, thirst, sleep cycles, and your energy levels. The hypothalamus also releases a compound called corticotropin-releasing factor (CRF) that drives your hormonal response to stress.

Once CRF is released, it travels to the pituitary gland, causing it to secrete a tongue-twisting hormone called adrenocorticotrophic that cues the adrenal glands to produce stress hormones, especially cortisol.

Did you know?
Cortisol is that magical hormone that boosts your body’s energy supply and keeps you on high alert during times of perceived danger.

The hypothalamus also triggers nerve cells to release norepinephrine, a naturally occurring chemical in the body that acts as both a stress hormone and a neurotransmitter. As soon as norepinephrine comes on the scene, your muscles become tight and your senses sharpen. At the same time, your adrenal glands release epinephrine, better known as adrenaline, which makes the heart pump faster and the lungs work harder to flood the body with oxygen. And all of this happens in the blink of an eye. (3)(4)

Once the threat has passed, the body returns to normal. Trouble starts when the stress response isn’t allowed to subside. Here’s why: When the stress response becomes constant, the HPA-axis remains active. Think of it like a stuck gas pedal that constantly revs the engine in your car, flooding it with a steady stream of gas (cortisol). Over time, this can lead to a dysfunctional HPA-axis—and that can result in severe adrenal exhaustion. Conditions related to HPA-axis dysfunction and adrenal exhaustion include cardiovascular disease, cognitive impairment, diabetes, gastrointestinal problems, obesity, skin rashes, asthma, arthritis, and depression. (5)

How stress affects the body

Consider this: At least 75 percent of all doctor office visits are for stress-related ailments and complaints. (6) Chronically high levels of stress hormones such as cortisol and norepinephrine can also suppress immunity, leaving patients vulnerable to everything from the common cold to more serious conditions, including some forms of cancer. This can be especially problematic for the elderly since their immune system becomes less efficient with age.

How can what goes on in your head have such a detrimental impact on your health? If you’ve ever gotten sick right after a stressful event, you’ve seen how stress can impact your immunity. Although the immune system is initially given a boost during the fight or flight response, if stress persists the nutrients needed to meet the demands of stress— particularly the B vitamins—are depleted. Living in a world of wall-to-wall stress also results in immune-suppressing levels of the stress hormones epinephrine and norepinephrine. High cortisol levels can put a damper on your natural killer cell activity, too. (7)

Cortisol can also have a negative impact on your cardiovascular system. Studies show that chronically high cortisol levels can increase blood pressure, blood sugar, cholesterol, and triglycerides—all factors that can boost your risk of hypertension, stroke, and heart attack. (8)(9)

woman lying on her couch with covers blowing her nose

Chronic stress can undermine your immune system and lead to a variety of health problems.

Other research reports that a chronic cortisol overdose can wreak havoc with your gastrointestinal system by either delaying the emptying of the digestive tract or by speeding up the amount of time it takes food and waste to pass through the colon. As a result, stress can cause heartburn, indigestion, nausea and vomiting, diarrhea, constipation, and belly pain. But the negative effects of stress don’t stop there.

Did you know?
Stress hormones can also trigger gastrointestinal inflammation and may explain the link between stress, irritable bowel syndrome, and inflammatory bowel disease. (10)

Stress can also make a pre-existing medical condition worse. People with diabetes are significantly affected by stress since physical or psychological stressors can inhibit insulin production. One clinical trial published in the journal Diabetes Care found that this can lead to more diabetic complications. (11) People with seizure disorders such as epilepsy also find that stress can trigger an attack. In one retrospective study, Dutch scientists compared the seizure activity of 30 epileptic patients suddenly evacuated because of an impending flood to 30 patients living outside the evacuation area. What they found was that one-third of the evacuees experienced a significant increase in the frequency of their seizures compared to those who had not experienced the flood-related stress. (12) Those suffering from asthma and allergies are also more susceptible to attacks following a stressful event. A survey of more than 10,000 college students found that, in addition to compromising the respiratory system, stress also increased the risk of eczema, skin rashes, and hives. (13)

When it comes to mental health, too much stress can lead to poor concentration, depression, and the uneasy feeling that we’re not really in charge of our own lives (14)(15). The Hopi Indians have a name for it – Koyaanisqatsi, or life out of balance.

close up of a calendar on an ipad with man editing the calendar

Overscheduling your life can set you up for stress overload.

What are the signs of stress

This 10-question quiz was created by INSEAD professor Manfred F. R. Kets de Vries and is designed to tell you exactly how close to the breaking point you are. (16) If you answer yes to six or more of these questions, you might want to find ways to manage your stress and embrace your inner calm.

  1. Do you feel that your life is out of control and that you have too many things on your plate?
  2. Do you often feel confused, anxious, irritable, fatigued, or physically debilitated?
  3. Are you having increased interpersonal conflicts (e.g. with your spouse, children, other family members, friends, or colleagues)?
  4. Do you feel that negative thoughts and feelings are affecting how you function at home or at work?
  5. Is your work or home life no longer giving you any pleasure?
  6. Do you feel overwhelmed by the demands of emails, messaging tools, and social media?
  7. Do you feel that your life has become a never-ending treadmill?
  8. Are you prone to serious pangs of guilt every time you try to relax?
  9. Have you recently experienced a life-altering event, such as a change of marital status, new work responsibilities, job loss, retirement, financial difficulties, injury, illness, or death in the family?
  10. When you are stressed out, do you feel that you have nobody to talk to?

Yes, you can stress less!

Even if you answered yes to all of the above questions, there are ways to manage your response to everyday stress. Lifestyle hacks—from massage to meditation—can help to keep you calm and healthy. Ditto for adopting a healthy diet. And don’t forget supplements. Adaptogens have a long history of helping users “adapt” to stressful situations. Even if you’re hit with stress day in and day out, a little stress management and self-care can help you stay in balance, no matter what life throws at you.

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  2. Coon D. Health, Stress & Coping. Introduction to Psychology, Exploration and Application. St. Paul: West Publishing Company, 1989.
  3. Jansen AS, Nguyen XV, Karpitskiy V, et al. Central command neurons of the sympathetic nervous system: basis of the fight-or-flight response. Science. 1995;270(5236): 644-6.
  4. Smith SM, Vale WW. The role of the hypothalamic-pituitary-adrenal axis in neuroendocrine responses to stress. Dialogues in Clinical Neuroscience. 2006; 8(4): 383–395.
  5. DeMorrow S. Role of the hypothalamic-pituitary-adrenal axis in health and disease. International Journal of Molecular Sciences. 2018;19(4):986.
  6. Salleh MR. Life event, stress and illness. Malaysian Journal of Medical Sciences. 2008;15(4):9-18.
  7. Dhabhar FS. Enhancing versus suppressive effect of stress on immune function: Implications for immunoprotection and immunopathology. NeuroImmunomodulation. 2009;16:300-17.
  8. Vogelzangs N, Beekman ATF, Milaneschi Y, et al. Urinary Cortisol and Six-Year Risk of All-Cause and Cardiovascular Mortality. Journal of Clinical Endocrinology & Metabolism, 2010; 95(11):4959-64.
  9. Stress Can Increase Your Risk for Heart Disease. Health Encyclopedia. University of Rochester Medical Center. Available at:
  10. Mertz H. Stress and the Gut. UNC Center for Functional GI & Motility Disorders. Available at
  11. Chiodini I, Adda G, Scillitani A, et al. Cortisol secretion in patients with Type 2 diabetes. Diabetes Care. 2007;30(1):83-8.
  12. Novakova B, Harris PR, Ponnusamy A, et al. The role of stress as a trigger for epileptic seizures: A narrative review of evidence from human and animal studies. Epilepsia. 2013:54(11):1866-76.
  13. Kilpeläinen M, Koskenvuo M, Helenius H, et al. Stressful life events promote the manifestation of asthma and atopic diseases. Clinical & Experimental Allergy. 2002;32(2):256-63.
  14. Eskildsen A, Fentz HN, Andersen LP, et al. Perceived stress, disturbed sleep, and cognitive impairments in patients with work-related stress complaints: A longitudinal study. Stress. 2017;20(4):371-8.
  15. Tafet GE, Smolovich J. Psychoneuroendocrinological studies on chronic stress and depression. Annals of the New York Academy of Sciences. 2004;1032:276-8.
  16. Kets de Vries MFR. The 10-Point Stress Audit. INSEAD Knowledge. Available at:


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