The Stress Response
The Stress Response
Stress causes the hypothalamus in the base of the brain to release CRH (corticotropin releasing hormone).
CRH then stimulates the anterior pituitary (also in the brain) to release ACTH (adrenocorticotropin releasing hormone).
ACTH causes the adrenal cortex (adrenals sit on top of your kidneys) to release glucocorticoids. The most well known one is called cortisol.
It takes just a few seconds for CRH levels in the blood to rise and also once the stress is over, the levels drop again very quickly.
In contrast, it takes several minutes for the process to result in the release of glucocorticoids and so their levels in the blood do not start to rise for several minutes and, similarly, it also takes time for them to reduce.
• CRH suppresses appetite.
• Glucocorticoids (incl. Cortisol) stimulate appetite.
This makes sense. At the beginning of a stressful event (lion attacking, sprinting to catch your food, running into a traffic jam on way to an important meeting, boss appearing just as you’ve realised you’ve missed including a vital point in your report…) then it is best that you don’t eat as you need the energy and blood that would be diverted to your gut for more important things like running and jumping and feeding your brain so that it can worry some more….
- At the first smell of stress, your blood levels of CRH go up and your appetite is suppressed.
In the middle of the stressful event, both CRH and glucocorticoid levels are high. This is the time your body and brain are working on resolving the problem and its still a good idea not to have much appetite (and since the effects of CRH on suppressing appetite are higher than those of glucocorticoids on stimulating appetite that’s what happens).
After the event has resolved, the CRH quickly dissipates. However, the glucocorticoid levels remain high for around a couple of hours after the event. This is great for recovery as glucocorticoids aid the immune response and healing and also
- stimulate appetite to replenish energy stores.
- Of course the type of foods your corticosteroids stimulate you to want are easy to digest, rapid energy replenishing foods like doughnuts and chocolate brownies…
Now take the sort of person who feels constantly stressed. They might behave something like this:
They are woken up several times during the night by young children and then sleep through the alarm clock.
- Panic as they think they will be late for work.
- Then calm down when they manage to catch the train.
- Then panic when the train is kept at a red light and is delayed after all.
- Then calm down when arrive at work and the boss is not in yet either.
- Then panics when an email comes in highlighting a task that they thought had been done.
- And so the day goes on, in a cycle of panic and relaxation.
- Or the official term: frequent intermittent stressors.
So what are their hormones doing all day:
- frequent short bursts of rapidly clearing CRH and, as a result of their slow clearance, almost constant elevated glucocorticoids.
- So stimulating an appetite for snacking and the wrong types of foods for a relatively sedentary lifestyle.
Of course, not everyone responds in the same way.
- Psychologically, different people respond differently to the same stressor. What is utter horror for one person may be hardly acknowledged by another (as they happily read the next chapter in their book as the train is held in the station!).
- Physiologically (or metabolically), one person’s liver may be more effective at breaking down the glucocorticoids out of their blood stream than another person’s.
Other effects of elevated glucocorticoid levels:
- The fat cells around your abdomen (also referred to as visceral fat) are more sensitive to glucocorticoids than other body fat cells. This means that when your glucocorticoid levels are higher, you lay down more fat as visceral fat. High abdominal fat levels are a strong risk factor for cardiovascular disease and other illnesses.
Other effects of stress on the gastrointestinal tract:
1. Rapid Emptying:
As we’ve already mentioned, in times of stress, the last thing your body needs to be doing is wasting energy on digesting food. So it diverts blood away to more important organs and stimulates your gut to empty. In your stomach and small intestine, large amounts of water are used to make your food in to a rich soup of food, enzymes, stomach acids and bile , etc., so that the nutrients can be digested and absorbed. Once it reaches your colon (or large intestine) then this liquid must be reabsorbed so that you don’t become dehydrated and you produce a nice semi-solid stool.
However, add a stress and your gut says, “empty now!” and rushes the whole process through resulting in some level of diarrhoea.
2. Irritable Bowel Syndrome
So the rapid emptying is achieved in response to what we call the sympathetic nervous system. This is stimulated in times of stress. In times of peace, the parasympathetic dominates and the gut gets on with calmly digesting, absorbing and gently pushing your food through with normal peristaltic gut contractions.
In contrast, the sympathetic nervous system is responsible for the increase large intestinal contractions in times of stress. People suffering from IBS, tend to be more susceptible to these gut responses and suffer correspondingly from bouts of cramping and intermittent diarrhoea (and reactive constipation).
I hope this has helped give you a bit more insight in to your responses and helps you understand some of your other symptoms i.e. lack of energy, which are probably partly in response to external stressors as well of course internal emotional factors such as perceived lack of performance, effectiveness, self- and external- dissatisfactions, happiness and fulfilment.
For these emotional factors remember that your thoughts reinforce themselves:
- Think and behave happily and you will be happy.
- Think negatively and you invite negativity.
Nature's intelligence functions with effortless ease. Grass doesn't try to grow, it just grows like flowers they just bloom. So when things don't go your way for the moment let go of the way you think they should be and realise there may be a bigger picture....; The known is our past. The known is nothing other than the prison of our past conditioning... stagnation, entropy, disorder, and decay.
Uncertainty on the other hand, is the fertile ground of freedom. Stepping into the unknown in every moment of our existence, ever fresh, ever new, always opens us to the creation of new manifestations...; without uncertainty life is just the stale repetition of outworn memories. You become the victim of the past and your tormentor today is your self left over from yesterday. DEEPAK CHOPRA