Cortisol the stress hormone – I am sure you have heard of this hormone before.
However, many people don’t realize its role in our body and the results of high Cortisol levels, especially for a long period of time. When chronically elevated, cortisol can have deleterious effects on weight, immune function, and chronic disease risk.
In this series, I will explain the physiological background and effects of Cortisol on our body. Then, we will go into more detail and point out the role of this hormone in cancer and diabetes development and weight loss.
Fortunately, exercise and nutrition are again one of our most powerful weapons to counteract Cortisol. Stay tuned for the last parts of this giant series, giving nutrition and exercise tips, to help you regulate your hormones and prevent future diseases!
Meet your Stress Hormone
Cortisol is a steroid hormone, produced from cholesterol and released in the cortex within the adrenal gland. The adrenal gland is located above our kidneys and has several layers in its cortex. The second of these three layers is responsible for synthesis and release of Cortisol.
Generally speaking, Cortisol is released (in normal levels) in stressful situations, low blood glucose sugar levels, waking up in the morning, exercising and according to natural cycles that tend to correlate to circadian rhythms. Cortisol can reach every cell in our body, thus it plays many roles in physiological processes in our body and homeostasis.
Synthesis and release
Cortisol’s release is increased by a part of our brain, called hypothalamus. It regulates our hormones, electrolytes, blood glucose levels, hunger, sleep and many other functions.
When blood glucose levels are low or in situations of acute stress, cells in our hypothalamus activate and release the regulating hormone for Cortisol, CRH (corticotropin-releasing hormone).
This hormone triggers cells in the anterior pituitary to secrete another hormone, called ACTH (adrenocorticotropic hormone) into the vascular system.
Once ACTH has reached the adrenal cortex, it activates cells in the second layer to release Cortisol.
ACTH does not only increase Cortisol levels, it is also important for regulating mineralocorticoids (important for electrolyte system), glucocorticoids and DHEA (sexual hormone, used to synthesize testosterone).
To sum this up, there are three instances regulating the release of Cortisol:
- Hypothalamus: CRH
Pituitary gland: ACTH
Adrenal gland: Cortisol release
The “Fight or Flight” Situation
I am sure you have heard of Cortisol in relation to the “Fight or Flight” response, along with its partner adrenalin, also called epinephrine, and noradrenaline, also called norepinephrine. The following situation is a draft to demonstrate the release and function of Cortisol, Adrenalin and noradrenaline in our body.
1. Individual faces a stressful situation: This could be an exam, an argue with a friend or even a dangerous situation such as facing a bear in the woods.
2. At first, noradrenaline is released, as the “fighting” hormone. As stress arouses, Adrenalin is released as well, also called the “flight/anxiety” hormone.
3. Noradrenaline and Adrenalin increase you heart rate, alertness in your brain and fatty acids from our body’s fat storage are released. Noradrenaline and Adrenalin are also the main hormones released while exercising.
4. If the stressful situation is not solved, hormonal changes occur and the hormonal cascade to release Cortisol is activated (CRH -> ACTH -> Cortisol), so that Cortisol is released from our adrenal glands.
5. Cortisol prepares our body to “fight back”, by increasing blood glucose levels and blood flow to our muscles. Also, it inhibits Insulin’s effects on our body to prevent glucose from being stored, so that it can be used as fuel.
6. Cortisol narrows our arteries. This increases blood pressure and more blood is pumped into our body.
7. Cortisol reaches our brain and further increases alertness, so we can fully focus on the stressful situation.
8. You face the situation and try to solve it (run away from the bear, solve the problem with your friend, study for your exam).
9. Once the stressful situation is over, the Hypothalamus inhibits Cortisol secretion and our body’s physiological processes return to normal.
Factors increasing Cortisol levels
Other than stressful situations, there are many factors that can trigger cells in our Hypothalamus to release Cortisol. The following are the most common.
Intense or prolonged aerobic exercise
Postmenopausal women: Low estrogen and melatonin levels lead to increase of Cortisol levels
Severe trauma, stressful events
Subcutaneous adipose tissue (fat stored in our skin)
Severe calorie restriction
Why we need Cortisol
As you can see, Cortisol play a big role in our body’s stress response. For our body, stress is an indicator of risk of death.
Thus, cortisol shuts down all “unnecessary functions” that use too much energy that is needed for survival. Reproduction and immune system, gastric system and many other functions in our body are reduced to minimal to allow our brain to fully concentrate on solving the situation. However, these effects of Cortisol are supposed to be short-lived.
Unfortunately, our modern lives are filled with stressful situations which leads to chronic high cortisol levels and development of many diseases, which I will explain in the following articles.
I hope you will find this new series useful!
I will include many tips to reduce stress in your daily life with proper nutrition and fitness as well.
Lastly, this series is going to go on for about a month. After that, at the beginning of may (I am thinking May 2nd), we are going to start the new 8- 10 weeks fat loss program!
This is not your average “lose 10 pounds in 2 days” program. I will be doing it with you and we will make sure to eat as much food as possible (cheats included), while preserving muscle mass and losing fat.
If you are excited and would like to join a community of motivated, inspirational people (mostly women ;)), join our facebook group! It is a private group and I don’t accept everyone … you need to prove to me that you are not a spammer and really want to join us on this health journey.
Wish you all a wonderful start of the new week. The next part of this series is going to be published on Thursday.
+ What I learned in medical school 🙂
Life of Meg