What is Adrenal Fatigue?

Maybe you’ve been told you have “adrenal fatigue” or have heard the term applied to someone who might be experiencing some form of “burnout”. Maybe you’re even familiar with the controversy around the existence of “adrenal fatigue” - a label that is technically not recognized as a formal diagnostic term by the medical community. Is it real? What are the symptoms that tend to be associated with this condition? If it’s not “adrenal fatigue”, what is going on in the body in these cases?

Adrenal Fatigue or Chronic Fatigue Syndrome?

Some may consider “adrenal fatigue” a misnomer for a set of symptoms better identified under the header of Chronic Fatigue Syndrome (CFS) or Myalgic Encephalomyelitis (ME). Others might consider it a lay term for generalized adrenal insufficiency such as Addison’s. Some researchers have even suggested that the terms CFS/ME are inadequate to capture the true extent of the condition. In this case, they have proposed a new term: Systemic Exertion Intolerance Disease or SEID. Either way, it may feel understandably confusing to navigate the conflicting opinions out there.

In this article, I’ll shed some much needed light on one of the hottest topics in healthcare. Whether this is a new area of health you haven’t yet heard about or one you consider yourself very well-versed in, this detailed and exciting tour of the most up-to-date science on the topic is bound to leave you considering some things you might not have previously!

Is There a Test For Adrenal Fatigue?

The simple answer is no. Given that the term “adrenal fatigue” is not a recognized diagnostic label for a medical condition, testing doesn’t formally exist. Several studies have even sought consistent biomarkers of “burnout” but findings were conflicted. However, for recognized conditions such as CFS/ME, the CDC does have some symptomatic criteria for diagnosis we’ll talk more about below.

What are the Symptoms?

According to data from the Institute of Medicine (IOM), an estimated 836,000 to 2.5 million Americans suffer from CFS/ME and the vast majority of them have not been diagnosed. Not only is diagnosis made difficult due to the variety of symptoms one may experience, but many of the symptoms present may be attributed to other types of conditions. Symptoms may also worsen over time for someone and can exist along a continuum of moderate to truly debilitating.

The symptoms typically associated with conditions such as CFS/ME may include:

Fatigue
Trouble falling asleep or staying asleep and waking unrefreshed
Unexplained body pain, aches, and inflammation
Difficulty with cognition and memory or “brain fog”
Mood changes
Tender lymph nodes in the neck or armpits
A sore throat that happens often
Digestive issues, like irritable bowel syndrome (IBS)
Chills and night sweats
Allergies and sensitivities to foods, odors, chemicals, light, or noise
Muscle weakness
Shortness of breath
Irregular heartbeat or dizziness upon standing

Diagnosing CFS/ME

The CDC lists 3 core criteria or primary symptoms for diagnosing CFS/ME and those include:

A significant loss of ability to perform daily activities that one could do before they became ill. This drop in activity level and tolerance along with fatigue must last six months or longer for a diagnosis. People with CFS/ME often have fatigue that is worse than your garden-variety tiredness arising after doing a hard activity. The fatigue in CFS/ME often exists even without doing an exceptionally difficult activity and resting/sleeping may not make it better.
Post-exertional malaise (PEM). This involves the acute worsening or flare-up of symptoms after a physical or mental stress trigger. This experience is commonly referred to as a “crash,” “relapse,” or “collapse.” It may take days, weeks, or longer to recover from a crash. Sometimes people may be house-bound or even completely bed-bound during crashes. Crash triggers can be unpredictable, though are often related to what the body perceives as a stressful event it didn’t tolerate well. A crash-triggering stressor for someone with CFS/ME will often be something that seems benign or unharmful to someone without this condition. We’ll talk more about triggers below.
Sleep problems. People with CFS/ME may not feel refreshed or energized after a full night’s sleep. Problems with insomnia - including falling asleep and staying asleep - are also common.

In addition to these 3 core criteria, the CDC also requires one of the following for diagnosis:

Problems with thinking and memory. This can include trouble remembering things and a feeling of “brain fog”.
Orthostatic intolerance. People with CFS/ME may be lightheaded, dizzy, weak, or faint while standing or sitting up. This may also include some changes in vision, such as blurred vision.

Beyond Adrenal Fatigue: A Deeper Understanding

So what is happening in these cases where the body seems to be unable to tolerate or adapt to stress effectively? Though there is no firm consensus across the board regarding the precise mechanism, there are many fascinating and strong evidence-based hypotheses.

But before we get into those details, it’s important to take a look at the history of these theories and where it all began.

The Science of Stress

Your body’s goal is to exist in a state of homeostasis. This is a state of equilibrium required to maintain the smooth functioning of thousands of chemical processes required to keep you healthy and alive. It’s a delicate balance that requires a lot of players. A stressor is any type of pressure applied to your body that may knock it out of homeostasis. What your body does to adapt to the stress is called a stress response.

The stress response system in your body is also called the neuroendocrine system. It relies on an orchestra of communication between the nervous system and the endocrine system. Simply put, it’s a system in charge of helping you adapt to whatever stressors come your way. It helps the body constantly adjust course to re-find homeostasis in the face of an ever-changing environment.

Pioneers of Stress Science

Many people attribute the first neuro-hormonal model of stress to Hungarian scientist Hans Selye in the 1930s. However, in reality, the physiologist Walter Cannon had paved the way for Selye by the 1920s. Selye’s work focused on identifying what he called “General Adaptation Syndrome” (GAS). According to him, GAS constituted the scope of the body’s stress response and it could take place in 3 phases:

An initial alarm phase
A stage of resistance or adaptation
An eventual stage of exhaustion and death

Selye’s insights were assimilated from his experiments with rodents but also his clinical observations as a medical student during the 1920s. As he tended to patients with diverse medical conditions such as tuberculosis, cancer, and burns, he noticed that despite their differing diagnoses, they had many similar symptoms. It was through identifying these common threads in symptoms that Selye began to imagine them being caused by a more general failure in the body’s ability to adapt to stress.

Later versions of the GAS model were applied to early ideas of “adrenal fatigue”. Some people suggested that the adrenals leading the charge in the stress response would work harder during acute stress, with chronic stress over time leading to “weakened” adrenals. However, as the esteemed neuroendocrinologist Robert Sapolsky so eloquently writes in his book about stress science, Why Zebras Don’t Get Ulcers,

“The army doesn’t run out of bullets…it is not so much that the stress-response runs out, but rather, with sufficient activation, that the stress-response can become more damaging than the stressor itself.”

With cases of chronic stress, we might not be seeing a state of “adrenal fatigue”, per se - but instead a system-wide change in function as the body tries desperately to adapt (without great success) to the flood of incoming stressors. The adrenals are but one part of the neuroendocrine or stress-response system. And while their function may be impaired during times of acute or even chronic stress, they may be only one part of a larger story of stress response unfolding.

The Neuroendocrine System

As mentioned earlier, the neuroendocrine system is your stress-response system. But what is it, exactly? What does it involve?

You can imagine this system as a cafeteria with a bunch of little tables. Each table in the cafeteria seats little cliques or groups of people who are able to carry on their own unique conversation at their table. However, these people may get up and head over to interact with the conversation at other tables as well. This is similar to how the neuroendocrine system works. The “conversation tables” happening in the neuroendocrine system are called axes. Axes are little groups of glands, locations, or other neurological structures that hang out together in conversation. What they talk about is focused at their table but may also involve and impact some other neighboring tables or axes as well. Together, they keep the adaptive conversation going and you have them to thank for your life!

Though, as we mentioned earlier, when the stress-response is over-activated, our life may be put at great risk.

Neuroendocrine Axes

Some of the most well-known neuroendocrine axes include:

The hypothalamus-pituitary-adrenal (HPA) axis
The hypothalamus-pituitary-gonadal (HPG) axis
The hypothalamus-pituitary-thyroid (HPT) axis
The gut-brain axis
The gut-liver axis
The adrenal-liver axis
The skin or cutaneous axis

Here are some examples of bodily functions controlled or influenced by the different axes of the neuroendocrine system:

Digestion and absorption of food
Blood sugar regulation
Sleep/wake cycles
Menstrual cycles and reproductive health
Immune system regulation, including modulation of inflammation
Mood and cognition
Body temperature, blood pressure, and heart rate
Exercise stamina and recovery
Muscle growth, repair, and tissue turnover
Other hormone levels, including those impacting menstruation, pregnancy and fertility, as well as those impacting metabolic rate

If you look at this list, you might notice that it looks a little familiar. These areas are also the sites of common complaints and symptoms in CFS/ME we listed above. They are also sites of common complaints for cases of stress overload, or what is more formally referred to as allostatic overload.

What is Allostatic Overload?

Allostasis is the active process of maintaining homeostasis. Allostatic load is the cumulative burden of chronic stress on the body. Allostatic overload is when stressors exceed the body’s ability to adapt or cope. Chronic allostatic overload has been associated with a higher risk for a number of diseases and conditions, including:

Cardiovascular disease
Diabetes
Some types of cancer
Impaired immune function, including heightened autoimmune risk
Digestive disorders
Migraines
Mental illnesses
Fatigue

Studies show that short-term stressors of different kinds may be beneficial. However, the same stress applied over longer periods of time may be very detrimental. This relates to the concept of hormesis. Hormesis, also known as the “U-shaped curve” in some cases, is a general term to describe a dose-dependent response to a stressor. What this means in simple terms is that too little of something and too much of the same thing can both cause equivalent stress and damage to the body. A great example of this phenomenon is in nutrition science, where deficiency of a certain nutrient may cause symptoms similar to those present when the nutrient is taken in excess. For example, too little iodine and too much can both cause goiter.

This is why finding the middle ground, or the “center of the U”, is so important for health.

What counts as stress, anyway? As I’ve mentioned in prior articles, any of the following may be considered stress by the body, depending on the dose:

Emotional drama or trauma
Physical activity/exercise
Fasting
Nutrient imbalances
Intolerances to foods, medications, or supplements
Injuries or infectious illnesses
Some herbal or bioactive compounds (including caffeine)
Alcohol
Environmental toxins/xenobiotic exposure
Exposure to allergens
Sleep deprivation
Blood sugar imbalances

Many things can also impact how our body interprets or copes with any of these stressors, such as:

Our age
Our sex
Our genetic predisposition
Our medical history and any current medical conditions
What other stressors we are exposed to simultaneously

As the body is gradually overwhelmed with stressors (coming from multiple sources) that it may not be equipped to adapt to, allostatic overload ensues. From there, your risk for many diseases and conditions, including fatigue, increases. Though we lack popular consensus in the medical community as to how to properly label and manage the broad spectrum of symptoms and conditions attributed at least in part to allostatic overload, there is strong evidence to suggest that actively working to address and manage stressors of every kind is crucial.

Not only do we see promising results in reducing emotional stressors in managing CFS/ME conditions, but addressing and reducing stressors from other origins is equally important. We know that nutritional components, for example, greatly impact neuroendocrine regulation and response.

Evidence-Based Therapies

Understanding more about the neuroendocrine system and how it works, you can see why the term “adrenal fatigue” has attracted so much criticism. You can also see why there is a need for a more accurate and full-bodied term for the fatigue conditions that may arise from chronic allostatic overload.

These conditions can be complex and difficult to manage. Perhaps one of the most important elements of managing CFS/ME or conditions of chronic allostatic overload is understanding crashes, triggers for crashes, and how each person’s response to stressors may be different. This means that what is “too much” of a given stressor for one person, may be well-tolerated by another.

Customizing a therapeutic approach in navigating crashes and crash triggers is best guided by a qualified medical professional with extensive experience working with these conditions. Medical assessments and therapeutic approaches that may be guided by your medical provider, including qualified nutrition professional, might include:

Any necessary blood work and other exams to rule out specific primary conditions with similar symptoms
A customized dietary approach to meet your unique nutrient needs and identify any food or supplement intolerances
A customized exercise program that includes appropriate levels of activity for your condition to avoid triggering crashes
Appropriate adjustments of medications
Emotional stress management techniques
Social support

Are Supplements a Good Idea?

In my clinical and professional opinion after working with thousands of CFS cases, this is very risky ground. Self-navigation around supplement use in CFS is not recommended and it’s very important to explore this with a highly qualified and experienced provider who knows their way around CFS management/recovery.

So far, the research looking at the use of various supplements or specific generic diets in CFS or similar conditions has found insufficient evidence to support their use. Some doctors are also concerned that supplements or vitamins sold as a treatment for adrenal fatigue could cause more harm than good - especially if they trigger crashes. One cautionary statement from The Endocrine Society says:

“If you take adrenal hormone supplements when you don’t need them, your adrenal glands may stop working and become unable to make the hormones you need when you are under physical stress. When these supplements are stopped, a person's adrenal glands can remain ‘asleep’ for months. People with this problem may be in danger of developing a life-threatening condition called adrenal crisis.”

As always, it’s best to proceed with any medication or supplement prescriptions or recommendations from a qualified healthcare professional.

Blood Sugar and Chronic Fatigue Syndrome

Some studies have suggested that CFS may be associated with metabolic syndrome and changes in glucose regulation, which can further worsen fatigue symptoms. Metabolic dysfunction related to altered ability to use fatty acids and amino acids as fuels is also seen in some research in CFS. Some suggest that this along with other changes in the body’s ability to use glucose may make these individuals more prone to hypoglycemic episodes as well. When blood sugar falls too low in hypoglycemia, this can act as its own independent stress on the body. Effectively managing blood sugar levels in those with CFS or similar conditions may therefore be an important component of therapy.