When we talk about stress, we think primarily of the stress hormone cortisol. And specifically, its effects when it is chronically elevated. But before we explore the effects of cortisol imbalances, let's have a look at the essential and healthy functions of cortisol.
1. The physiologically normal functions of cortisol
Cortisol is a very important component of our metabolism. In normal physiology, cortisol follows a 24-hour rhythm (called the circadian rhythm). At the beginning of sleep, cortisol levels are at their lowest; at the end of sleep, they rise and peak just minutes before waking. Cortisol plays an important role in initiating wakefulness and raising blood glucose levels in preparation for our morning activity.
The 24-hour rhythm of cortisol also affects the brain, autonomic nervous system, heart, and cardiovascular system. Cortisol is one of the most important hormones in human physiology. Almost all cells in the body have cortisol receptors.
In contrast to adrenaline, which rapidly prepares the body for immediate action in the fight-or-flight response with increased heart rate and energy surges, cortisol steadily accumulates in response to prolonged stress, fine-tuning the body's metabolism by elevating blood glucose levels and temporarily suppressing non-essential functions such as the immune and digestive systems. This evolutionary adaptation enhances alertness and diverts energy towards dealing with sustained threats.
So, similar to insulin, cortisol is a very important factor in our health. Problems arise when the stress response is chronically activated. An overdose of cortisol and other stress hormones disrupts your body’s natural processes and increases the risk for many health problems, such as obesity, chronic inflammation, and sleep disorders.
2. Causes of elevated cortisol
Psychological stress
Physical stress (excessive exercise, injury, surgery, or illness).
Sugar consumption/high insulin levels.
Stimulants (coffee, appetite suppressants, diet pills)
Sleep deprivation
Aging
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One of the most important stress-independent causes of high cortisol is high insulin.
Cortisol is a counter hormone to insulin. When insulin levels are too high, it can push blood glucose levels too far down, whereupon the cortisol response converts proteins into glucose.
On the other hand, elevated cortisol (from other causes) can drive blood sugar up and trigger an insulin response. This destructive feedback loop can lead to higher cortisol levels, higher insulin levels, and ultimately cortisol and insulin resistance.
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Lack of sleep, in particular, can lead to another negative feedback loop: On the one hand, lack of sleep can contribute to higher cortisol levels; on the other hand, high cortisol levels can lead to anxiety, inhibit melatonin release, and disrupt sleep.
Aging itself can contribute to higher cortisol levels through a gradual decline in growth hormone. Growth hormone is produced during sleep and is an important antagonist of cortisol - in other words, it keeps cortisol levels in check. The best thing you can do about it is to ensure a good night’s sleep and get more sleep.
3. Symptoms of chronically high and chronically low cortisol
When cortisol levels are elevated for an extended period of time, the receptors that are supposed to absorb the hormone begin to block it. In other words, you can develop cortisol resistance. This is very similar to insulin resistance. The amount of cortisol in your blood may even appear normal. But the cells are no longer sensitive to cortisol, and cortisol no longer works. That's why it's good to pay attention not only to symptoms related to high cortisol levels but also to low cortisol levels or cortisol resistance.
Symptoms of high cortisol:
Abdominal fat
High blood pressure
Poor sleep
Loss of proteins (muscles, hair, skin, collagen, bones)
Suppressed immune system
High cholesterol level
Low vitamin D levels
Heartburn (acid reflux)
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Symptoms of low cortisol or cortisol resistance:
Inflammation
Autoimmune diseases
Allergies
Asthma
Memory problems
4. How chronically elevated cortisol levels contribute to overweight and obesity
The main way chronically elevated cortisol levels contribute to overweight and obesity is by triggering gluconeogenesis (the conversion of proteins to glucose) and promoting insulin resistance.
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Cortisol is a so-called glucocorticoid. One of its main functions (as the name suggests) is to increase the availability of glucose in the blood. In the liver, high levels of cortisol increase gluconeogenesis from amino acids (proteins). In the presence of cortisol, muscle cells decrease glucose uptake and instead increase protein breakdown to supply gluconeogenic amino acids to gluconeogenesis.
5. A few tips if you are suffering from chronically elevated cortisol
Eat enough protein: Even with elevated cortisol levels, where you convert more of that protein into glucose and have a harder time losing weight, it's better to get the protein you need through your diet. Cortisol is such a powerful driver of gluconeogenesis that it does not spare any protein mass in your body when it is elevated. Muscles, organs, tendons, ligaments, skin, and even bones are consumed as substrates.
Avoid high carbohydrate meals: Remember that high cortisol, in this case, is not caused by actual glucose needs but by an inappropriate and chronic fight-or-flight response. The best defense is to lower cortisol levels.
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Eating carbohydrates will not help you lower cortisol levels and stop gluconeogenesis but may actually make the problem worse. That's because when your blood sugar rises too quickly and then drops quickly, it triggers a stress response in your body and causes cortisol to be released again. Low carb and keto diets reduce the stress response during carbohydrate digestion, resulting in less cortisol being released.
Improve your sleep.
Build walks or other forms of exercise into your daily routine.
Continually improve your environment in terms of stress triggers, daily stressors, and even stress-inducing people in your life. Learn to say «no» and balance your schedule.
Explore daily relaxation routines and rituals. Depending on your character and preferences, meditation or breathing exercises, for example, can make a significant difference. Others may respond better to regular yoga sessions, walks in nature, or sauna visits.
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Find more nutrition facts and tips in my book FOOD FOR HEALTH, available now in the shop and on all Amazon Marketplaces!
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