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  • Writer's pictureMichael Cordova

Stress, Cortisol and Inflammation

In any given week in England, 6 in 100 people will be diagnosed with generalised anxiety disorder (Mind) In the UK, over 8 million people are experiencing an anxiety disorder at any one time (Mental Health UK). These reactions are normal in our current climate, but they can also take a physical and mental toll with an increase in cortisol levels.

Focusing on your mental wellbeing and lowering stress levels can help in reducing inflammation and help our bodies cope better when we do become ill in general, especially at this time of year.

Firstly, we will look at what cortisol is and how it affects us physically and mentally. Then we will look at how floating and the infrared sauna can help reduce stress and inflammation.

What is Cortisol?

Cortisol, a glucocorticoid (steroid hormone), is produced from cholesterol in the two adrenal glands located on top of each kidney. It is normally released in response to events and circumstances such as waking up in the morning, exercising, and acute stress. Cortisol’s far-reaching, systemic effects play many roles in the body’s effort to carry out its processes and maintain homeostasis. When chronically elevated, cortisol can have deleterious effects on weight, immune function, and chronic disease risk.

Cortisol (along with its partner epinephrine) is best known for its involvement in the “fight-or-flight” response and temporary increase in energy production, at the expense of processes that are not required for immediate survival. The resulting biochemical and hormonal imbalances (ideally) resolve due to a hormonally driven negative feedback loop.

The following is a typical example of how the stress response operates as its intended survival mechanism:

1. An individual is faced with a stressor.

2. A complex hormonal cascade ensues, and the adrenals secrete cortisol.

3. Cortisol prepares the body for a fight-or-flight response by flooding it with glucose, supplying an immediate energy source to large muscles.

4. Cortisol inhibits insulin production in an attempt to prevent glucose from being stored, favouring its immediate use.

5. Cortisol narrows the arteries while the epinephrine increases heart rate, both of which force blood to pump harder and faster.

6. The individual addresses and resolves the situation.

7. Hormone levels return to normal.

So, what’s the problem? In short, the theory is that with our ever-stressed, fast-paced lifestyle, our bodies are pumping out cortisol almost constantly, which can wreak havoc on our health. This whole-body process, mediated by hormones and the immune system, identifies cortisol as one of the many players. But isolating its role helps put into context the many complex mechanisms that lead to specific physiological damage.

Whole-Body Effects of Elevated Cortisol

Blood Sugar Imbalance and Diabetes Under stressful conditions, cortisol provides the body with glucose by tapping into protein stores via gluconeogenesis in the liver. This energy can help an individual fight or flee a stressor. However, elevated cortisol over the long term consistently produces glucose, leading to increased blood sugar levels.

Theoretically, this mechanism can increase the risk for type 2 diabetes, although a causative factor is unknown.1 Since a principal function of cortisol is to thwart the effect of insulin—essentially rendering the cells insulin resistant—the body remains in a general insulin-resistant state when cortisol levels are chronically elevated. Over time, the pancreas struggles to keep up with the high demand for insulin, glucose levels in the blood remain high, the cells cannot get the sugar they need, and the cycle continues.

Weight Gain and Obesity Repeated elevation of cortisol can lead to weight gain.2 One way is via visceral fat storage. Cortisol can mobilize triglycerides from storage and relocate them to visceral fat cells (those under the muscle, deep in the abdomen). Cortisol also aids adipocytes’ development into mature fat cells. The biochemical process at the cellular level has to do with enzyme control (11-hydroxysteroid dehydrogenase), which converts cortisone to cortisol in adipose tissue. More of these enzymes in the visceral fat cells may mean greater amounts of cortisol produced at the tissue level, adding insult to injury (since the adrenals are already pumping out cortisol). Also, visceral fat cells have more cortisol receptors than subcutaneous fat.

A second way in which cortisol may be involved in weight gain goes back to the blood sugar-insulin problem. Consistently high blood glucose levels along with insulin suppression leads to cells that are starved of glucose. But those cells are crying out for energy, and one way to regulate is to send hunger signals to the brain. This can lead to overeating. And, of course, unused glucose is eventually stored as body fat.

Another connection is cortisol’s effect on appetite and cravings for high-calorie foods. Studies have demonstrated a direct association between cortisol levels and calorie intake in populations of women.3 Cortisol may directly influence appetite and cravings by binding to hypothalamus receptors in the brain. Cortisol also indirectly influences appetite by modulating other hormones and stress responsive factors known to stimulate appetite.

Immune System Suppression Cortisol functions to reduce inflammation in the body, which is good, but over time, these efforts to reduce inflammation also suppress the immune system. Chronic inflammation, caused by lifestyle factors such as poor diet and stress, helps to keep cortisol levels soaring, wreaking havoc on the immune system. An unchecked immune system responding to unabated inflammation can lead to myriad problems: an increased susceptibility to colds and other illnesses, an increased risk of cancer, the tendency to develop food allergies, an increased risk of an assortment of gastrointestinal issues (because a healthy intestine is dependent on a healthy immune system), and possibly an increased risk of autoimmune disease.4,5

Gastrointestinal Problems Cortisol activates the sympathetic nervous system, causing all of the physiologic responses previously described. As a rule, the parasympathetic nervous system must then be suppressed, since the two systems cannot operate simultaneously. The parasympathetic nervous system is stimulated during quiet activities such as eating, which is important because for the body to best use food energy, enzymes and hormones controlling digestion and absorption must be working at their peak performance.

Imagine what goes on in a cortisol-flooded, stressed-out body when food is consumed: Digestion and absorption are compromised, indigestion develops, and the mucosal lining becomes irritated and inflamed. This may sound familiar. Ulcers are more common during stressful times, and many people with irritable bowel syndrome and colitis report improvement in their symptoms when they master stress management.5 And, of course, the resulting mucosal inflammation leads to the increased production of cortisol, and the cycle continues as the body becomes increasingly taxed.

Cardiovascular Disease As we’ve seen, cortisol constricts blood vessels and increases blood pressure to enhance the delivery of oxygenated blood. This is advantageous for fight-or-flight situations but not perpetually. Over time, such arterial constriction and high blood pressure can lead to vessel damage and plaque build-up—the perfect scenario for a heart attack. This may explain why stressed-out type A (and the newly recognized type D) personalities are at significantly greater risk for heart disease than the more relaxed type B personalities.6

Fertility Problems Elevated cortisol relating to prolonged stress can lend itself to erectile dysfunction or the disruption of normal ovulation and menstrual cycles. Furthermore, the androgenic sex hormones are produced in the same glands as cortisol and epinephrine, so excess cortisol production may hamper optimal production of these sex hormones.5

Other Issues Long-term stress and elevated cortisol may also be linked to insomnia, chronic fatigue syndrome, thyroid disorders, dementia, depression, and other conditions.4,5

The Good News So far, it may seem as though stressed-out folks are destined for failed health despite their best intentions. Fortunately, there is much we can do for ourselves to reverse the path of destruction. The best approach to keeping cortisol levels at bay is mastering stress management. We are able to do this effectively through Floatation Therapy and the Infrared Sauna.

But how can Floating and Infrared Saunas help?


In our fast paced society stress management is of the utmost importance. Floatation therapy has been used successfully in clinical stress management and has been found to reduce blood pressure, cortisol levels, and other stress-related neuro-chemicals such as norepinephrine, adrenaline and ACTH 11, 12. (Turner & Fine, 1983; Turner & Fine, 1991; Dierendonck, 2005).

These neuro-chemicals are known to trigger the fight-or-flight response, which is great if we need to react quickly to life-threatening situations. But not when our body overreacts to stressors that are not life-threatening, such as traffic jams, work pressure, and family difficulties. By eliciting the relaxation response, floatation therapy puts us in a calm, unshakable, steady, balanced, and totally concentrated state of mind that allows us to manage stress effectively.

Previous research has presented floatation therapy as a tool to help reduce stress and increase relaxation. Although, many studies have used healthy subjects, only a few studies have surveyed floating for people with anxiety. Recent research published in PLoS ONE by Dr Justin Feinstein (2018) 13, specifically noted how floating affects people with signs of stress, depression, and anxiety.

The study included 50 participants indicating a wide variety of stress-related symptoms and anxiety disorders such as social and generalized anxiety, panic, and post-traumatic stress. 30 healthy individuals also involved in the study offer context. After experiencing floatation therapy, 47 out of 50 patients felt floating could be an efficient intervention for minimizing levels of anxiety. As well as this, every participant requested to try the treatment again. Therefore, the study suggests that floating may be successful treatment for anxiety since after just one float participants mood improved and anxiety was reduced.

Floatation therapy has the ability to trigger the relaxation response in the body. The relaxation response, which is the opposite of the fight-or-flight response, impacts the parasympathetic nervous system, reducing blood pressure, heart rate, and slowing breathing.

Infrared Sauna

We know that stress increases the levels of cortisol in the body, and it turns out that cortisol in turn lowers the body’s ability to fight off germs. Stress makes you more susceptible to catching a cold and becoming ill. Cohen, S., Tyrrell, DA., Smith, AP, (1991)14.

In 2015 a Finnish study by Mero, A. Tornberg, J., Mäntykoski, M. Puurtinen, R. (2015) 15 found that far infrared sauna bathing with its 3-4 cm penetration into tissue reduced cortisol levels in men who had just exercised. A review study by Shanshan S, Wang X, Chiang J. Y, Zheng L. (2015) 16 also found far infrared therapy to be helpful for lowering cortisol.

Offsetting heightened stress hormones like cortisol will help your body stay balanced and ready to fight off any bugs or viruses that comes along.

Infrared therapy is like giving yourself a passive cardio workout – whenever you need it!

The infrared sauna heats your muscles with infrared rays and produces an increase in blood flow similar to regular exercise. In fact, blood flow during infrared sauna use has been reported to rise from a normal rate of 5-7 quarts per minute to as much as 13 quarts per minute. Matsushita K, Masuda A, Tei C. (2008) 17.

The elevation in body temperature from a sauna session also produces an increase in blood flow that mirrors the benefits of a passive cardiovascular workout. Regular infrared sauna use – especially in the mid-infrared range – has been shown to significantly stimulate blood flow, even after your health sauna session is completed.

A 2018 meta-analysis of seven studies by Källström M. et al (2018) 18. concluded that infrared sauna sessions were associated with short‐term improvement in heart functioning for patients with heart failure.

When your body is fighting an infection like a cold or flu, the immune system causes an increase in temperature, anywhere from 100.9°F (38.3°C) or higher, which is considered a fever. This elevated temperature creates a less suitable environment for these destructive bugs.

Infrared saunas work similarly to a fever in the body. The infrared heat penetrates the skin and works deep in the tissues, raising core body temperature to about 102°F (39°C). The body responds to this simulated “fever” by stepping up its immune response and mobilizing the Th1 branch of the immune system. This branch is antiviral and antibacterial, as opposed to the antiparasitic and anti-allergic Th2 system.

Additionally, increasing the body temperature to within the range of a fever has been shown by Evans S.S, Repasky E.A, Fisher D.T. (2015) 19. to improve the adaptive immune response. This helps the body “remember” the microbes you have been exposed to, and to be better prepared to fight them next time around. Near-infrared light activates white blood cells and increases antibodies against pathogens.

In fact, a NASA study showed this same near infrared therapy, delivered by LEDs deep into body tissue, can quadruple cell health and tissue growth Dr. Whelan et al. (2000) 20.

Several studies have shown that LEDs stimulate white blood cell production and collagen growth by increasing energy at the cellular level.

A study done at the Medical College of Wisconsin demonstrated that LED-produced near infrared (NIR) helps promote cell health and regeneration.

Most recently, and something we are excited to learn more about, Dr Rhonda Patrick talked about Sauna use and immunity with regards to COVID-19. Here is what she had to say:

“No data suggest that sauna use or other modalities of heat stress such as steam showers or hot baths will have any effect on COVID-19 illness. However, robust evidence suggests that sauna use promotes mild hyperthermia, which, in turn, induces a wide array of beneficial physiological responses.

These responses reduce oxidative stress and inflammation and activate cellular defence systems such as heat shock proteins, which provide protection against many diseases. Data from a 2017 study suggest that sauna use reduces the risk of developing certain chronic or acute respiratory illnesses, including pneumonia, by up to 40 percent.

Sauna use reduced the incidence of common colds in 25 participants who used the sauna one to two times per week for six months compared to 25 controls who did not. It is noteworthy that it took three months before sauna use had a protective effect. The mechanism by which frequent sauna use reduces the incidence of pneumonia and colds is unknown but might be related to modulation of the immune system.

Levels of white blood cells (especially lymphocytes, neutrophils, and basophils) are increased in both trained and non-athletes after sauna use. While these findings are interesting, they are still preliminary and larger studies are needed to confirm. Increasing evidence suggests that certain heat shock proteins play a role in both innate and adaptive immunity.

Heat shock proteins can directly stimulate innate immune responses, such as the maturation and activation of dendritic cells and the activation of natural killer cells. This indicates there may be a direct role for heat shock proteins in regulating the innate immune response, which plays an important role in the body's ability to fight off a disease that it has never been exposed to before”.

Summary Cortisol is a fascinating hormone that is important to understand on many levels. Understanding the science behind it, including its behaviours and relationships to other biochemical components, the immune system, and health outcomes, is crucial to our success in treating people who seek intervention for stress, illness, fatigue, and other common complaints. Investing in your mental and physical health can help in part in reducing inflammation, improving your overall health and boosting your immune system.

1. Andrews RC, Herlihy O, Livingstone DEW, Andrew R, Walker BR. Abnormal cortisol metabolism and tissue sensitivity to cortisol in patients with glucose intolerance. J Clin Endocrinol Metab. 2002;87(12):5587-5593.

2. Epel ES, McEwen B, Seeman T, et al. Stress and body shape: Stress-induced cortisol secretion is consistently greater among women with central fat. Psychosom Med. 2000;62(5):623-632.

3. Epel E, Lapidus R, McEwen B, Brownell K. Stress may add bite to appetite in women: A laboratory study of stress-induced cortisol and eating behavior. Psychoneuroendocrinology. 2001;26(1):37-49.

4. Jones DS, Quinn S (eds). Textbook of Functional Medicine. Gig Harbor, Wash.: Institute for Functional Medicine; 2006.

5. Weinstein R. The Stress Effect. New York: Avery-Penguin Group; 2004.

6. Sher L. Type D personality: The heart, stress, and cortisol. QJM. 2005;98(5):323-329.

7. Vining RF, McGinley RA. The measurement of hormones in saliva: Possibilities and pitfalls. J Steroid Biochem. 1987;27(1-3):81-94.

8. Vining RF, McGinley RA, Maksvytis JJ, Ho KY. Salivary cortisol: A better measure of adrenal cortical function than serum cortisol. Ann Clin Biochem. 1983;20(Pt 6):329-335.

9. Hellhammer DH, Wust S, Kudielka BM. Salivary cortisol as a biomarker in stress research. Psychoneuroendocrinology. 2009;34,(2):163-171.

10. Kudielka BM, Hellhammer DH, Wust S. Why do we respond so differently? Reviewing determinants of human salivary cortisol responses to challenge. Psychoneuroendocrinology. 2009;34(1):2-18.

11. 'Effects of Relaxation Associated with Brief Restricted Environmental Stimulation Therapy (REST) on Plasma Cortisol, ACTH, and LH' - John W. Turner, Jr., and Thomas H. Fine, Medical College of Ohio (1983)

12. 'Restricting environmental stimulation influences levels and variability of plasma cortisol' - John W. Turner, Jr., and Thomas H. Fine, Medical College of Ohio (1991)

13. 'Examining the short-term anxiolytic and antidepressant effect of Floatation-REST' - Justin S. Feinstein, Sahib S. Khalsa, Hung-wen Yeh, Colleen Wohlrab, W. Kyle Simmons, Murray B. Stein, Martin P. Paulus, Laureate Institute of Brain Research (2018)

14. ‘Psychological stress and susceptibility to the common cold’ - Cohen S, Tyrrell DA, Smith AP, Carnegie Mellon University (1991)

15. ‘Effects of far-infrared sauna bathing on recovery from strength and endurance training sessions in men’ - Mero, A. Tornberg J, Mäntykoski M, Puurtinen R, University of Jyväskylä (2015)

16. ‘Far-infrared therapy for cardiovascular, autoimmune, and other chronic health problems: A systematic review’ - Shanshan S, Wang X, Chiang J. Y, Zheng L. Hefei University of Technology (2015)

17. Efficacy of Waon Therapy for Fibromyalgia’ - Matsushita K, Masuda A, Tei C. Kagoshima University Hospital (2008)

18. ‘Effects of sauna bath on heart failure: A systematic review and meta-analysis’ -Källström M, Soveri I, Oldgren J, Laukkanen J, Ichiki T, Tei C,Timmerman M, Berglund L, Hägglund H, Uppsala University (2018)

19. ‘Fever and the thermal regulation of immunity: the immune system feels the heat’ - Evans S.S, Repasky E.A, Fisher D.T. Roswell Park Cancer Institute (2015)

20. ‘The NASA Light-Emitting Diode Medical Program- Progress in Space Flight and Terrestrial Applications. CP504, Space Technology and Applications International Forum’ - Whelan et al (2000)

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