Stress…..The silent killer!!

According to Britannica, the fight-or-flight response is a “response to an acute threat to survival that is marked by physical changes, including nervous and endocrine changes, that prepare a human or an animal to react or to retreat.” (1) This response was essential for the survival of our hunter-gatherer ancestors, such as being able to respond to a potential attack by a hungry predator. Our problem today is constant activation of this stress response by non-life-threatening stressors, such as work, traffic jams, relationship difficulties, worry, anxiety, fear, aggression, and anger.

So, what is the stress response?

This part will dig into the pathophysiology of the stress response. It can get a little confusing but don't worry, I also made some graphics to simplify this as best I can!! Here we go!

When the brain perceives a dangerous or life-threatening situation, it sends signals to the amygdala region of the brain which is primarily associated with emotional processes. If the amygdala certifies that there is a threat, then a signal is sent to the hypothalamus region of the brain. The hypothalamus functions as the control center, communicating with the rest of the body through the autonomic nervous system, which controls involuntary functions such as breathing, blood pressure, heartbeat, opening and closing of blood vessels and small airways in the lungs.

The autonomic nervous system has two components, the sympathetic and parasympathetic nervous systems. The sympathetic nervous system is like a gas pedal in a car, it triggers our body functions to respond to dangers. The parasympathetic nervous system is the brake, allowing our body to slow back down after the danger has passed to resume normal body functions.

The hypothalamus sends signals to the adrenal glands via the sympathetic nervous system. This stimulates the release of epinephrine, aka adrenaline, into the bloodstream. Epinephrine prepares the body physically for the fight or flight, increasing the performance of the heart and lungs, rerouting blood to organs necessary for survival such as the muscles, diverting from unnecessary parts (digestion and bladder), increases muscle tension to provide extra strength and speed, increases blood clotting function to prevent excessive blood loss, and increases immune system function to protect from infections, if bitten by a predator.

If the stress persists, then the hypothalamus activates another pathway in the stress response – the hypothalamic-pituitary-adrenal (HPA) axis to sustain the immediate reaction activated by the sympathetic nervous system and epinephrine. The hypothalamus sends a signal to the pituitary gland to release corticotropin-releasing hormone (CRH). CRH stimulates the release of adrenocorticotropic hormone (ACTH). ACTH stimulates the release of cortisol from the adrenal glands. Cortisol increases blood pressure, blood sugar, and suppresses the immune system. These actions are to provide the body with a boost of energy, hence, to run away or fight the threat. When the threat passes, cortisol levels fall, and the parasympathetic nervous system puts on “the brakes” to return your body into a state of bal

And this is the stress response….

What are the health effects of chronic stress?

Not all stress is bad. If we did not have such an effective stress response many more of our ancestors likely would have been killed. In short amounts, stress can be appropriate or even beneficial in our lives. The issues with health effects from stress occur when this response becomes chronic.

Persistent epinephrine stimulation increases blood pressure which can damage blood vessels and arteries, raising the risk of heart attack and stroke. Elevated cortisol levels contribute to buildup of fat tissue and weight gain, increased appetite, and decreased function of the immune system. (2,3)

Chronic stress is linked to many other health problems including depression, anxiety, Alzheimer’s disease, Parkinson’s disease, memory problems, hormonal / menstrual problems, sexual dysfunction, low sexual desire, skin and hair problems, gastritis, gastric ulcers, ulcerative colitis, irritable bowel, poor sleep, and cancer. (2-7)

Many of the conditions listed above are either triggered or exacerbated by chronic, low-level inflammation. Through disturbing the balance of the immune system, chronic stress induces inflammation peripherally and centrally. (2,4)

What can you do to control your stress?

It is almost impossible to have no stress in our lives. However, there are many things we can do to help with stress management:

• Try a relaxation technique such as breathing exercises, guided imagery, meditation, repetitive prayer, yoga, or tai chi.

• Increase your physical activity. Exercise can reduce inflammation but intensity matters. (8) Intense, long exercise can lead to higher levels of inflammatory mediators which might increase the risk of injury, infection, and chronic inflammation. This phenomenon had been seen with heavy training scheduled or endurance competitions, such as marathons or long-distance cycling. Moderate or vigorous exercise with appropriate resting periods can achieve maximum benefit. (8-11) The “Goldilocks Zone” for physical activity coincides with the CDC physical activity guideline of at least 150 minutes per week of moderate-intensity aerobic exercise or 75 minutes per week of vigorous-intensity aerobic exercise. (12,13) The talk test is a rule of thumb to gauge the intensity of your work out: if you're doing moderate-intensity activity, you can talk but not sing during the activity; if you're doing vigorous-intensity activity, you cannot say more than a few words without pausing for a breath. (13)

• Eat a healthy whole foods diet. All processed foods can cause inflammation. Processed food includes food that has been cooked, canned, frozen, packaged or changed in nutritional composition with fortifying, preserving, or preparing in different ways. Frozen fruits and vegetables are minimally processed and are generally okay to include in your diet, just watch out for added ingredients and flavors. The Mediterranean diet has been well studied in the prevention of chronic diseases (14), this may be a great place to start.

• Keep a journal or write about your thoughts to help clear your mind.

• Schedule time for yourself for hobbies, reading, relaxation, going out for a walk, etc.

• Organize and prioritize what you need to accomplish at home and work and remove unnecessary tasks.

• Avoid unhealthy ways of managing your stress, such as using alcohol, tobacco, drugs or excess food.

• Social support and community. Whether its friends, family, community, religious organization, and others, they can be a source of help and support when you are feeling stressed.

• Get professional help if you feel that you cannot manage your chronic stress on your own.

• Get adequate sleep. Lack of sleep causes the body to react as if it is in stress, releasing more cortisol.

We are currently experiencing an evolutionary-environmental mismatch. Modern life has led to a mismatch between what is causing our stress and our body’s stress response which was designed for short term activation. There has not been enough time for evolution and natural selection to catch up.

Stress is part of our human existence. You may not be able to change your current situation, but I hope this information can help you take steps to manage the impact these things have on you and your health.

References:

1. https://www.britannica.com/science/fight-or-flight-response

2. Liu, Y. Z., Wang, Y. X., & Jiang, C. L. (2017). Inflammation: The Common Pathway of Stress-Related Diseases. Frontiers in human neuroscience, 11, 316. https://doi.org/10.3389/fnhum.2017.00316

3. Fink, G. (Ed.). (2019). Stress: Physiology, Biochemistry, and Pathology: Handbook of Stress Series (Vol. 3). Cambridge, Massachusetts: Academic Press.

4. Mayo Clinic Staff. (2016). Healthy Lifestyle: Stress management. Mayo Foundation for Medical Education and Research. Retrieved from: http://www.mayoclinic.org/healthy-lifestyle/stress-management/in-depth/stress-symptoms/art-20050987?p=1

5. American Heart Association Editorial Staff. (2021). Lower stress: how does stress affect the body. Retrieved from: https://www.heart.org/en/healthy-living/healthy-lifestyle/stress-management/lower-stress-how-does-stress-affect-the-body

6. Shirui, D., Yongzhen, M., Yumin, W., Bo, X., Qianjin, L., Ming, Z., Xiaoling, L., Yong, L., Wei, X., Guiyuan, L., Can, G., & Zhaoyang, Z. (2020). Chronic Stress Promotes Cancer Development. Frontiers in Oncology, 10, 1492. https://doi.org/10.3389/fonc.2020.01492

7. Thaker, P.H, Lutgendorf, S.K., & Sood, A.K. (2007). The Neuroendocrine Impact of Chronic Stress on Cancer, Cell Cycle, 6(4), 430-433. https://doi.org/10.4161/cc.6.4.3829

8. Paolucci, E.M., Loukov, D., Bowdish, D.M.E., & Heisz J.J. (2018). Exercise reduces depression and inflammation but intensity matters. Biological psychology, 133, 79-84. https://doi.org/10.1016/j.biopsycho.2018.01.015.

9. Cerqueira, E., Marinho, D.A., Neiva, H.P., & Lourenco, O. (2020). Inflammatory effects of high and moderate intensity ecersice – A systematic review. Frontiers in Physiology, 10, 1550. https://doi.org/10.3389/fphys.2019.01550

10. Gleeson M., Nieman D.C., Pedersen B.K. (2004). Exercise, nutrition and immune function. Journal of Sports Sciences,22, 115–125. https://doi.org/10.1080/0264041031000140590

11. Maughan R.J., & Gleeson, M. (2010). The Biochemical Basis of Sports Performance (2nd edition). Oxford, UK: Oxford University Press.

12. O’Keefe, J.H., O’Keefe, E.L., & Lavie, C.J. (2018). The Goldilocks zone for exercise: Not too little, not too much. Missouri medicine, 115(2) , 98-105.

13. U.S. Department of Health and Humans Services. (2018). Physical activity guidelines for Americans (2ndedition). Retrieved from: https://health.gov/sites/default/files/2019-09/Physical_Activity_Guidelines_2nd_edition.pdf

14. Romagnolo, D.F., & Selmin, O.I. (2017). Mediterranean diet and prevention of chronic diseases. Nutrition today, 52(5), 208-222. https://doi.org/10.1097/NT.0000000000000228

15. Macrovector. (unknown). Peripheral autonomic nervous system. [digital image]. Retrieved 03/26/2022, from: https://www.dreamstime.com/nervous-system-realistic-chart-human-peripheral-autonomic-nervous-system-sympathetic-spinal-cord-neurons-signal-communication-image179551587