Cortisol is an awkward inheritance. Once upon a time it had a very real purpose. Even today it still serves it’s original purpose when given the correct opportunity, in situations like earthquakes, tsumanis, attempted murder, robbery and the humble, but basic, accident.
Depending on what you read it may also regularly serve it’s purpose by helping the body fight intestinal infection. More on that later.
But modern living has a way of activating prehistoric safety valves with unintentional consequences. Cortisol is one of these safety valves and right now, I am being reintroduced to the consequences of activating it when it wasn’t suitable.
What is cortisol?
For the complete bible on cortisol then you can’t beat Wikipedia. Cortisol is a corticosteroid hormone which is produced by the adrenal gland. Known as the “stress hormone”, it is most often associated with its production in response to stress and anxiety.
Cortisol is frequently believed to have the primary purpose of helping the body react to stress, triggering the “fight or flight” reaction to situations. However, I’ve found an interesting hypothesis from Charles Weber (also quoted by Wikipedia) which suggests that the primary purpose of cortisol is assisting the body’s resistance to infection, specifically intestinal disease, and that it’s impact on the “fight or flight” response is just an added bonus.
What does cortisol do to you?
The headline impacts of cortisol include:
- counteraction of insulin, contributing to hyperglycemia;
- stimulation of gastric acid secretion which in turn increases loss of potassium to the stomach;
- inhibition of sodium loss from the small intestine (so far only recorded in small mammals);
- acting as an anti-diuretic;
- lowering bone formation (due to the potassium loss);
- weakened activity of the immune system – this one confused me, but it seems that by briefly weakening the immune system and creating perfect circumstances for the immune system to operate, when cortisol then reduces again the immune system can work more effectively than before;
- shutting down the reproductive system, increasing the chance of miscarriage or causing temporary infertility;
- increasing sensitivity to adrenaline;
- cooperation with adrenalin to create memories of short-term emotional events;
- increasing blood pressure;
- reducing histamine secretion and therefore acting as an anti-inflammatory.
This is a strange combination of effects from a single hormone. Some of these clearly link to the “fight or flight” instinct, such as the increased sensitivity to adrenaline, hyperglycemia and increased blood pressure. Potentially even the reduced histamine secretion and shut down reproductive system (in a stressful time of famine, having offspring would cause problems) could be linked to the more extended period “fight or flight” requirement.
Others seems to point more clearly to the infection resistance, such as the changed ratio of sodium to potassium, the reduced histamine secretion (again) and the impacts on the immune system.
Problems of cortisol in the modern world
Cortisol seems to be principally designed for short term bursts. As you can probably imagine, prolonged periods of heightened cortisol levels could result in long-term illness from a weakened immune system and osteoporosis from the lack of bone formulation. Long-term exposure has also been shown to result in damage to cells in the hippocampus and impaired learning.
The increased sensitivity to adrenalin, which will also be produced if you are in a stressful situation, has it’s own collection of negative impacts on the body if you are exposed to it for a long time. Yet again, I turn to Wikipedia which notes that the main effects of adrenaline are to boost supply of oxygen and glucose to the brain and muscles and to suppress non-emergency bodily processes, such as digestion.
But so many things in our modern world have been shown to increase both cortisol and adrenaline. Commuting, sleep deprivation, burnout, severe trauma or stress, burnout and caffeine have all been tarred with the accusation of increasing one or both of cortisol and adrenaline. Worryingly, one study also suggested that some formulations of combined oral contraceptive pills could increase cortisol levels in young women who perform whole-body resistance exercise training.
Cortisol and adrenaline are no longer brief, rarely experienced hormones. Instead our bodies are adjusting to long-term exposure to these hormones and modern circumstances can create a vicious circle. The adrenaline can reduce our ability to sleep and process our food correctly. The increased risk of intestine infection from poorly processed food and the lack of sleep increases cortisol levels. The increased cortisol makes us hypersensitive to adrenaline. A minor stress at work, probably caused by lack of sleep, or a bad drive home gives you another small boost of adrenaline but you are now hypersensitive to it…
Cortisol and resistance training
As a brief diversion, there can be many reasons why stress impacts on resistance training and performance. Not least the mental challenges of trying to focus your effort on the bar when your mental strength is waining. However, I suspect there is also a link between poor resistance training and the fact that cortisol can cause temporary infertility. After all, Testosterone is a reproductive hormone, and it is testosterone that aids in resistance training.
Once I am unable to perform optimally in the the weights room, I then find that the calories I am putting in don’t get used in my workout so then they get converted to fat instead. As a woman, the balance of calories is very fine, so it can take only a couple of dud workouts before I have lost my leanness.
Managing cortisol
Relaxation and therapy seem to be the best ways to manage cortisol levels. In fact, there’s a whole study to show that laughing and humour can reduce cortisol levels! There seems to be an argument for dosing with vitamin C and black tea too.
I’ve also found it interesting that supplementing with magnesium after working out has a positive effect on reducing cortisol levels, but only after aerobic exercise, not resistance training.
Back at square one
My recent stress at work had it’s own cortisol and adrenaline impact. I stopped sleeping well and I started to struggle with various gym exercises. Without changing my diet or my workouts I gained a noticeable bottom in a single week. After all that hard effort that I put into stripping it off in October too.
Care and relaxation over the Christmas period has helped me gain control over my stress levels and, following some other experimentation over Christmas (more on that another time), the need for a hard 4 week fat-strip has come to the fore, despite having promised myself that I wouldn’t ever strip fat in the winter again. We’ll see how that goes.
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