Do you have ongoing fatigue, been diagnosed with chronic fatigue syndrome and trying to determine what's going on with your body? In this article, we look at some of the overlooked hormone causes of fatigue. In a previous article we looked at the three main causes of fatigue. Here we will discuss the physiological causes of fatigue that may have been overlooked. We specifically look at the things that can go wrong with the hypothalamus and pituitary because of stress. In addition, how stress can ultimately lead to a decreased production of important hormones that regulate energy and your bodily functions.
If you want to understand some of the overlooked hormone causes of fatigue, keep readings.
Hypothalamic Control And Cause Of Fatigue
The image below looks at is some of the controlling factors via the hypothalamus to the pituitary. This is also know as the hypothalamic pituitary axis. Most of the hormones in our body are controlled centrally by the hypothalamus and the feedback loops that occur through the pituitary and the hypothalamus. Interruptions in the feedback loops can cause global reduction in hormones, not just in one hormone system but many hormone systems.
The hypothalamus produces pulsatile rhythmic signals by way of hormones that cause the pituitary to then produce hormones as well. The hormones that are produced from the pituitary, target the end organ or the gland to produce the hormones that many of us are familiar with. These are things like cortisol, thyroid hormone, testosterone, etc. This process or system is referred to as the hypothalamic-pituitary - "whatever organ is involved." This could be the adrenals, the testes, the thyroid etc. For instance, you might see the hypothalamic-pituitary-adrenal axis or hypothalamic-pituitary- testicular access. So that's how those connections are referenced.
To make it more clear what happens in the dysfunctional state, let's look at an example like production of cortisol. In the case of cortisol, the hypothalamus produces a hormone called corticotropin releasing hormone. This hormone stimulates the pituitary to then produce ACTH (Adrenocorticotropin Releasing Hormone). The ACTH then goes on to the adrenal glands to stimulate them to produce cortisol and several other hormones. The cortisol levels then feeds back to the pituitary and shut off the ACTH production. It also feeds back to the hypothalamus to reduce the amount of corticotropin releasing hormone produced.
It turns out that your hypothalamus is part of a bigger neural network in the brain referred to as your limbic system. One of the big parts of what the limbic system does is it processes or is the center of our emotions. It is referred to as the emotional center in the brain. Stress, whether it's real or imagined, can cause the body to produce an appropriate amount of cortisol via this same mechanisms described above. In other cases, it could cause production of excess or deficient amounts of cortisol. Ideally it would produce the appropriate amounts of cortisol but sometimes there is dysfunction the hypothalamic response., as we will see below.
The same kind of signals are involved with thyroid hormone and testosterone production. When it comes to stress, cortisol can actually feed back to dampen the response that comes out of the hypothalamus for all of the hormones. So it can reduce the amount of gonadatropin releasing hormone and thyroid releasing hormone as well. When you are under a lot of stress, real or imagined you may have less hormone output. Also depending on how your systems are wired, you may produce more cortisol than you need to. You may perceive a higher threat (in a low threat situation) and this causes your body to down regulate the amount of these hormones produced.
Hypothalamic-pituitary-adrenal axis Hormone Cause Of Fatigue
When it comes to overlooked causes of fatigue, there is evidence in fatigue and chronic fatigue, being a problem in the hypothalamic-pituitary-adrenal axis (HPA axis). For some, it is thought to be a dysfunction in that axis. The dysfunction is in the response of your body producing cortisol and also how the cortisol feds back to the hypothalamus. Where does the dysfunction come from?
Acute traumatic experiences can dysregulate the stress response. Early childhood development trauma (which is more chronic) can also do this. Developmental trauma occurs when there are a lot of stressors in early childhood during development of the nervous systems. The stress input from the environment at early ages lead to a learned stress reponse. We can say that the nervous system is adapted and thereby sensitized to the stressors. This dysregulated nervous system and stress response can lead to a dampened response or an excess response depending on stressor (and the learned response). This phenomenon is clearly evident and well documented in acute PTSD. The acute trauma can also trigger an inappropriate cortisol response and that leads to dysfunction in the hypothalamic-pituitary axis. It is becoming more apparent that same kind of thing can happen from low level repeated stressors in our bodies, in adulthood and more commonly early childhood development.
In these cases the hormones from the pituitary can be measured in your blood. Measuring them can allow you to see that there are deficiencies. When it comes to overlooked causes of fatigue this is something that we see especially in post-traumatic stress disorder. Here is a link that goes int o more detail on PTSD and HPA dysfunction, if you are interested.
This study shows clearly how that cortisol feeds back on the hypothalamus. It also goes into a lot of detail it's a lot of biochemistry that is more recently being discovered and how all the feedback works. What it is shows is within the hypothalamus, there is the gonadotropin releasing hormone neuron. This neuron gets fed back on. This feedback is what causes the pituitary to produce FSH and LH. These hormones stimulate testosterone production in males and for females their estrogen and progesterone. We can see that things like stress can feedback and lead to a reduction in the amount of gonadotropin releasing hormone that is released. There are other things that can influence the feedback too like the actual hormones themselves, inflammation, drugs, metabolic things. The purpose of this is to show the relationship of stress on the axis. You can substitute corticotropin releasing hormone or thyroid releasing hormone here. We assume that the same types of feedback mechanisms are in place for all of these. With the difference being in the case of thyroid, it is neuron that stimulates the pituitary to produce TSH and is inhibited by thyroid hormone.
How Stress Causes Fatigue in Sensitized Individuals
The overall gist of it is that stress can have a negative impact on the amount of stimulation your glands are getting to then produce the appropriate amounts of hormones. Depending on how your stress response system is wired you may have an inappropriate amount of hormones being produced.
If you think this might be happening to you, one of the things you would want to do is check all the pituitary hormones. Also look at the amount of hormones that are being produced from the end organs like cortisol, thyroid hormone, testosterone. If you are not producing large enough amounts of the pituitary hormone and there's also a small amount coming out of the glands themselves, it suggested a dysfunction axis. For instance, if you have low luteinizing hormone and low testosterone or low ACTH and low cortisol, suggests that some of this may be occurring. If this is the case, then you want to look more closely at your stress response. This is easier said than done but there are things you can do, medicines you can take to help that response.
If you are someone that has ongoing fatigue that is one thing you should look at. A lot of people do have high stress levels but it's really about the stress response and how your systems are designed through development
That should give you a better understanding of some overlooked hormone causes of fatigue. If you have questions about the content in this article, please ask it in the comment section below.
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