What Causes Adrenal Fatigue? (Part I)

This is the first article in an ongoing series. Make sure to check out the next articles when you’re finished with this one:

The common assumption is that stress causes adrenal fatigue. While this holds true, the source of stress might not be what you think.

When you think of stress, what comes to mind?

Work?
Relationships?
Responsibilities?
Commitments?
Finances?
Deadlines?

The above are commonly associated as stress. Often, they are not enough to cause adrenal fatigue on their own. Instead, adrenal fatigue comes about by four specific types of stress. Only one of which is similar to the given examples.

The four potential causes of adrenal fatigue

There are four categories that Dr. Thomas Guillioms outlines as the main contributors to adrenal fatigue (1) :

Percieved stress
Glycemic dysregulation
Inflammatory signals
Circadian disruption

Perceived Stress

This is the category we all think of when talking about stress. It’s the work, family, relationship, financial etc. stressors. While this certainly plays a role in adrenal fatigue, often, it’s not the cause.

Circadian Disruption

Your HPA axis is linked to mechanisms that control your sleep-wake cycle. The sleep-wake cycle is governed by the twenty-four hour light-dark cycle we have adapted to. Night shifts and sleep deprivation are common causes of adrenal fatigue. (2)

Inflammatory Signals

Cortisol is a powerful anti-inflammatory hormone. Both acute and chronic inflammation trigger the HPA axis to increase cortisol levels in order to resolve the inflammation. If your body is required to excrete large amounts of cortisol on a daily basis, it will eventually lead to adrenal fatigue. (3)

Glycemic Dysregulation

Glycemic dysregulation is a fancy word for blood sugar imbalance. Factors that cause blood sugar imbalances, like poor diet, lack of sleep, lack of exercise, will also dysregulate the HPA axis. So, if you’re skipping breakfast, and eating high sugar meals, you could be setting yourself up for adrenal fatigue. (4)

How does adrenal fatigue develop?

I would like to introduce you to the terms metabolic reserve and allostatic load. These terms serve as the foundational principles that adrenal fatigue (HPA axis dysfunction) is built upon.

Metabolic Reserve
Metabolic reserve is the buffer that allows our stress-response system to maintain resilience in the face of stress. (5) Think of metabolic reserve as a bank account. When you practice meditation, you make a deposit to your bank account and your balance grows. When you undergo stress, you make a withdrawal from your bank account.

So long as your account balance remains above zero, your metabolic reserve remains intact. Of course, having more money in your account is advantageous as it better equips you to deal with unexpected stress. Should your balance go into the red (negative), your body no longer has the capital (metabolic reserve) to handle incoming stressors. It is at this stage that adrenal fatigue begins.

You have a finite amount of resources within your body to deal with all of life’s stress. These resources are your metabolic reserve.

Allostatic Load
Allostatic load measures the total amount of stressors upon our system and the cost this places on our body. (6) If you have a minor argument with your beloved, the allostatic load is likely quite small. Should you be battling a serious bacterial infection, the allostatic load is very high. The higher the allostatic load, the greater the stress placed on our body.

There are three basic processes that illustrate how allostatic load leads to our body’s inability to adapt to stress (7):

Frequent stressful events that reduce the ability to adapt
- Ex) Travelling to multiple time zones for work on a regular basis
A stress response that does not end
- Ex) A bacterial infection in your digestive tract
Inadequate or failure to respond to a stressor
- Ex) High blood sugar that is not being addressed through dietary changes

From an evolutionary perspective, our body’s stress response system is best designed to deal with immediate stressors. Think, encounter with a bear. During this instance, cortisol is excreted in order to transfer sugar (glucose) to your muscle cells. This transfer of energy ensures your muscles are ready to either attack the bear (fight) or run from the bear (flight).

In this example, the stress is short lived, after running away from the bear, your body can return to a state of relaxation (homeostasis) because the stress is now gone. This type of stress is what our body is ideally adapted for.

Fast forward to modern times and you will see that this type of stressful situation is rare. Stress today is chronic, long lasting, and often occurs with little to no reprieve.

Today’s chronic stress depletes our metabolic reserve.

Pair that with minimal training or utilization of stress reduction techniques (we rarely make deposits to our bank account) and you have a recipe that is fit for developing adrenal fatigue. This is why the symptoms of adrenal fatigue describe so many of us in western cultures.

What is cortisol?

Cortisol is a steroid hormone that affects many different functions in the body:

Helps with controlling blood sugar levels,
Regulates metabolism,
Helps reduce inflammation,
Assists with memory formulation,
Helps with salt and water balance and,
Helps control blood pressure.

In a healthy body, cortisol levels rise just before waking. They then rise even higher (to their highest point of the day), thirty minutes after waking. Then, a gradual decline of cortisol occurs as the day progresses. Before bed, cortisol should be at its lowest point of the day.

While we sleep, levels gradually begin to rise and the cycle starts again the next day. This fluctuation of cortisol levels is known as a diurnal rhythm. (9)

How does stress cause adrenal fatigue?

To better explain stress’s effect on our body, a three-stage model is used to explain the way adrenal fatigue progresses (10):

Stage 1 – Acute HPA axis activation
Stage 2 – Stress maladaption
Stage 3 – HPA axis down-regulation

Stage 1 – Acute HPA axis activation:

You’re involved in a minor car accident. You suffer from whiplash but no broken bones. This is the acute stage of HPA axis activation.

In order to deal with inflammation (brought on by the whiplash injury) and the psychological stress of being in a motor vehicle accident, cortisol levels increase. When we see an increase in cortisol levels on a patient’s lab, it is indicative of the body undergoing a stress response.

The goal of treatment should be to identify the cause of stress and take the necessary steps to reduce it. One should follow a set sleep schedule. This includes going to bed and waking at consistent times each day. And, avoiding electronics before bed.

Stage 2 – Stress maladaptation:

Continuing with the motor vehicle example, you’ve been undergoing physiotherapy and chiropractic care now for three months. Your neck is still in a great deal of pain. For the first time in your life, you suffer from migraines. This stage occurs after stressors have been present for long periods of time.

In stage 2, your body reacts to having ongoing high levels of cortisol by a process called down-regulation. (11) When down regulating, your brain instructs the adrenal gland to lower cortisol levels. This is an inappropriate reaction – you’re stressed, yet your body is telling itself “no need to respond”. This should occur only after your neck pain is alleviated, not before.

Stage 3 – HPA axis down-regulation:

It’s been just shy of a year; the neck pain and headaches have not changed. Your doctor has given you the diagnosis of fibromyalgia and referred you to the chronic pain clinic. In addition to pain, you feel exhausted and experience brain fog throughout the day. Aside from an antidepressant, nothing else seems to help with the pain levels.

Our body creates a state of low cortisol in order to preserve its metabolic reserve. Remember, cortisol is a stress hormone. Long-term states of high cortisol are incredibly exhausting to our system. (12)

At this stage, most treatment therapies will seem ineffective. Recovering from this stage requires long-term commitment. On average, healing and recovery from stage three take in excess of a year.

The state of low cortisol prevents the body from removing inflammation. Raising cortisol levels are required in order to overcome the injury/illness. Treatment from stage three adrenal fatigue should be focused on raising cortisol levels.

Ok, you’ve now got the foundation information required to understand what causes adrenal fatigue.

Looking for more information about adrenal fatigue? Check out our other blog posts.

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