The following chart shows the stages of adrenal fatigue. It was originally called the General Adaptation Syndrome.
The General Adaptation Syndrome (GAS) is included in most psychiatry text books.
We will explain each of the stages in more detail below. However....first a little information about the doctor that discovered adrenal fatigue.
The Stages of Adrenal Fatigue are based on the work of Dr Hans Selye. He called what happens under chronic stress the General Adaptation Syndrome.
Dr. Hans Selye was a Canadian endocrinologist, who spent several years studying the affects of chronic stress. What he documented from years of experiments is essentially the stages of adrenal fatigue.
The following article describes the work of Dr Selye. It is from the Journal of Neuropsychiatry, which is the Official Journal of the American Neuropsychiatric Association.
Dr Selye exposed rats to various stressful stimuli and observed a pattern in response to continued stress, which is illustrated in the chart above.
In reality, more than just the adrenal glands are affected by chronic stress. This is why there are so many symptoms (see List of Symptoms). He called it the General Adaptation Syndrome.
If more doctors knew about his work, they would understand Adrenal Fatigue.
There are different stages of the General Adaptation Syndrome. The timing and duration seems to be longer in humans than in the rats studied
Dr Selye exposed rats to stress such as:
Regardless of the source of stress, the response was the same.
In the rats, during the period from 6 to 48 hours after the stressor was introduced, Dr. Selye noted that the rats experienced a decrease in the size of various organs.
The thymus, spleen (both important for immune system), lymph glands and liver all decrease in size2.
Fat tissue was lost, edema (fluid retention) developed, there is a loss in muscle tone, a fall in body temperature, loss of cortical lipoids and adrenaline secreting cells from the adrenal medulla.
The immune system is weakened during this stage, which is why people under stress are more prone to becoming sick.
If the chronic stress continues, the progression through the stages of adrenal fatigue continues.
During the second stage of the Adrenal Fatigue (or the General Adaptation Syndrome), as chronic stress continues, you adapt to stress and have an increased ability to deal with stress. At this point, the adrenal glands become greatly enlarged2 , which makes sense since they are being asking to produce a large amount of adrenal hormones.
In the rats, Stage 2 started 48 hours after the introduction of the stressor, and continued for 1 to 3 months.   In humans, Stage 2 can go on for decades, depending on how severe the stress is, how many sources of stress, nutrition, etc.
During this stage, you can feel like an energy machine. No amount of stress seems to bother you.
Since you feel great, you don't realize you are charging towards the next stage of adrenal fatigue....Stage 3..... and will eventually crash.
You are likely Sympathetic Dominant at this point. This means that that
stressed side of your nervous
system is dominant over the calm side.
The constant triggering of the sympathetic nervous system makes you sympathetic dominant, which gives you an above average stress response.
You probably have developed fast reflexes and an exaggerated startle response at this point.
During Stage 2 of the General Adaptive Syndrome, you will probably not seek out medical help. Why would you? You feel great.
You feel like a machine and can handle more stress than normal since your enlarged adrenal glands are capable of producing high levels of epinephrine and other hormones.....non stop.
You can handle more stress than others, probably have more libido, are very strong for your size and basically feel great. Unfortunately, the fun does not last.
There is eventually a price to pay as you continue to progress through the stages of adrenal fatigue.
For more detailed information, see the article:
Stage 2 Adrenal Fatigue
Although it is possible to 'adapt' to chronic stress for a long period of time. As you move through the stages of Adrenal Fatigue, it catches up with you and the immune system collapses.
As Dr Seyle documented in the General Adaption Syndrome, Stage 3 begins after 1 to 3 months in rats. In humans, the progression to Stage 3 can take many years.
Dr Seyle noted that the symptoms in Stage 3 closely match the symptoms in Stage 1. The rats lost their resistance to stress and organs begin to fail again like they did in Stage 1.
When you get to this point.....you have entered adrenal burnout.
For more detailed information, see the article:
Stage 3 Adrenal Fatigue
Thinking back through my progression through the stages of adrenal fatigue, I don't really remember Stage 1. Stage 1 is fairly short lived. Stage 1 may have even occurred when I was in the womb.
However, in hind sight, I definitely remember Stage 2. I was an energy machine all my life until about 36 years old.
In my early 30's, I drove myself incredibly hard at work and at the gym. No amount of stress was too much at work.
And I would work out 7 days per week. On a typical Saturday, I would bike to the gym, lift weights, play racquet ball and then bike home(as hard as I could).
And I could lift more weight at the gym that was normal for my size. I was probably producing a very high amount of adrenaline at all times, stuck in Sympathetic Dominant mode.
I remember thinking:
this is not normal.....and it wasn't.
As I progressed through the stages of adrenal fatigue, I definitely remember the change from Stage 2 to Stage 3.
The first problem to show up was some minor anxiety, then a loss in libido, then a complete collapse into adrenal burnout. Then a very long journey to figure out what happened.