Original of this article was published on ZRT Laboratory Blog. Last reviewed: May 2026.
Practical Takeaway: When adrenal glands become fatigued — typically as a result of prolonged, repetitive stress — the output of key regulatory hormones, like ‘master stress hormone’ cortisol, is diminished.
Following my recent re-reading of Dr. James Wilson’s 2001 pioneering book, Adrenal Fatigue: the 21st Century Stress Syndrome, I took his advice and for the first time in months slept in on a Saturday morning. That day there was such a difference in my energy I decided to go with another of his suggestions and took a short nap on Sunday. Again I felt much better; after a 15 minute doze I was energised without the usual evening crash.
As a health educator I know better than to subscribe to the ‘you snooze you lose’ approach to life, but catnaps or sleeping in have been a rare indulgence. I always figured that as long as I slept 6–7 hours most nights, ate healthily, worked out and took plenty of vitamins, I had nothing to worry about. But upon my second reading of this eye-opening book, the wide-ranging symptoms, causes and effects of adrenal fatigue hit me like a ton of bricks: I’m one of them — one of the estimated 80% of adult Americans who at some point in their lives will experience some level of adrenal fatigue.
A Condition That Can Wreak Havoc with Your Life
When the adrenal glands become fatigued — typically as a result of prolonged, repetitive stress — their output of key regulatory hormones, particularly cortisol, ‘the master stress hormone,’ is diminished. Taxed adrenals may still function, says Dr. Wilson, but well below optimal level. That makes it tough to meet the demands of their job, and undermines the body’s ability to adjust to stress, stabilise blood sugars, and muster immune defences against disease.
The characteristic pattern of adrenal fatigue is a disrupted cortisol rhythm — low in the morning when you need it most, with a second wind late at night when you should be winding down. Our All Day Cortisol Test (LCMS) measures cortisol across four time points throughout the day, revealing exactly this kind of diurnal disruption and giving you and your practitioner the data needed to address it.
Dr. Wilson’s Symptom Checklist: Do Any of These Sound Familiar?
As a cause of what ails us, these telltale symptoms of adrenal fatigue are more often than not overlooked or misdiagnosed:
- Difficulty getting up in the morning
- Not fully awake until after 10am
- Need caffeine to get going
- Energy low from mid to late afternoon
- Better energy after 6pm until around 9pm
- Second wind from around 11pm to 1am
- Snacks on salty or sweet foods and caffeine to keep going
- Feels run down
- Harder to bounce back from illness or other stresses
- Difficulty concentrating and thinking clearly
- Lower libido
- Poor sleep
The more of these symptoms you have, and the more persistent they are, the more likely you are to be walking around with undetected adrenal fatigue. To turn that scenario around, the resource section of the book points you in the direction of saliva testing to detect and help correct the problem. Our Adrenal Function Saliva Test Kit (LCMS) measures cortisol and DHEA-S across multiple time points from a simple at-home saliva collection — the same approach recommended by Dr. Wilson and widely used in functional medicine to assess adrenal status.
People Vary Greatly in Their Ability to Respond to and Withstand Stress
An illness, life crisis or difficult, unresolved situation can drain the adrenal resources of even the healthiest person. Certain factors including poor diet, substance abuse, too little sleep and rest, social, emotional, or physical pressures, injury, chronic pain, and/or exposure to environmental toxins can overwhelm the adrenals, making us more susceptible to long-term illness.
For those who want a broader picture of how chronic stress is affecting their hormonal and thyroid health alongside adrenal function, our Advanced Hormone, Stress & Thyroid Health Test Kit combines cortisol, DHEA-S, sex hormones and thyroid markers in a single at-home test — with specialist interpretation to guide next steps.
After reading Dr. Wilson’s book you will come away feeling like you just earned an honorary PhD on the adrenal glands and their life-preserving role in the body. You will be totally clued in to the symptoms, causes and effects of this ubiquitous disorder and what it really feels like to suffer from adrenal fatigue. And you will learn to recognise whether you are one of the 80%, and what you can do to turn that equation around and stay healthy.
“Adrenal fatigue remains one of the most under-diagnosed illnesses in the US; many physicians are still not familiar with it. That is why I wrote this book, because once recognised, adrenal fatigue can be treated. You can get better.” — Dr. James L. Wilson, ND
Original of this article was published on ZRT Laboratory Blog.