Why does my body feel less than optimal? I am tired quite often and mentally foggy. Weight gain and depression (on and off) have come along with that.

To some extent, the answer to this question will be different for everybody, depending on their life circumstances, genetic inheritance, childhood, and even experience in the womb. But underlying just about every health problem is one powerful factor: your cortisol level.

It’s hard to overstate the centrality of cortisol to our overall health and well-being. Cortisol is the primary stress hormone manufactured by our adrenal glands. It has a tremendous effect on just about every system in our bodies, from hormones to digestion, immunity, and the nervous system.

Cortisol levels play a huge role in weight gain, mental clarity, anxiety and depression, motivation, and overall feelings of vitality or fatigue. Cortisol also affects our skin and hair, our blood pressure and circulation, and our lungs, muscles, and bones.

The X Factor

Cortisol is the “X factor” involved in just about every one of our illnesses, symptoms, or suboptimal days. When our cortisol levels are optimal, we feel terrific. When our cortisol levels are less than optimal—too high, too low, or not following their proper cycle throughout the day—we feel “off.” This may manifest as being foggy, irritable, tired, or unmotivated. You may also be plagued by symptoms, everything from weight gain to frequent colds to sleep problems.

Cortisol is central to just about every health problem we face, which makes sense when we remember that stress is a primary condition of life, and cortisol is the stress hormone. Cortisol is literally the medium through which stress affects us. But cortisol is also the medium through which we experience energy, vitality, and well-being.

This is why, as a practitioner, my first step in treating virtually every patient I see is to determine where cortisol levels have varied from their optimal levels and then find ways to optimize them. Once we get the cortisol levels back to their optimal state, good health will surely follow.

Optimal cortisol, optimal health

Cortisol is produced by our adrenal glands, two small organs that sit on top of our kidneys. When we perceive a threat to our life, security, or safety, our adrenal glands set off a primal stress response involving a multi-step chemical cascade in which several hormones are triggered. The end result of the process is cortisol.

Besides controlling the stress response, cortisol also helps us follow our circadian rhythms. Optimal cortisol levels are highest in the morning—in fact, the rising cortisol levels wake you up. Ideally you should be able to wake up, energized and alert, without an alarm clock.

Throughout the day, optimal cortisol levels gradually fall, following a nice, smooth downward curve, until finally by evening they are low enough to allow you to fall asleep. Your body uses sleep time to make more cortisol. It occurs primarily during the seventh and eighth hours of sleep, which is why getting a full night’s sleep is so crucial to overall good health.

The effects of everyday stress

Optimal cortisol rhythm is often disrupted. However, when stress persists cortisol levels are less likely to return to optimal and more likely to either remain at a stress-induced level or become depleted.

Too much cortisol disrupts the digestion and immune systems, as well as the production of hormones related to thyroid function, metabolism, growth, and reproduction. Excess cortisol levels also cause us to feel anxious, depressed, achy, and agitated, unable to settle down and often unable to sleep.

Too little cortisol, on the other hand, causes us to feel exhausted, depressed, and unmotivated. Cortisol at the wrong times of day—anything other than that nice, smooth downward curve—disrupts energy levels, mood, immune function, digestion, menstrual cycles, and sleep patterns.

If your adrenal glands aren’t recovering well from stress, they can produce one, two, or all three of those suboptimal conditions. In fact, just about any time you’re not feeling “100 percent” you are likely to be experiencing suboptimal cortisol levels. These suboptimal results don’t show up on standard medical tests, which tend to detect only extreme adrenal dysfunction.

Testing for cortisol

There is a validated laboratory test for less extreme variations in cortisol levels. This test measures cortisol levels in the saliva at four key times during the day (it is called the 24-hour cortisol saliva test). This allows us to see both how far our cortisol levels have strayed from their optimal levels and at which times of day they are suboptimal.

Because cortisol is so central to our health and well-being, I recommend that my patients determine their cortisol levels using this saliva test. All but a handful of my patients suffer from suboptimal levels, usually without realizing it. Perhaps this is not surprising, when you consider how much stress we all experience and how accustomed we have become to feeling less than our best!

When your cortisol levels are where they should be, you can almost always count on a strong immune system (both defending you from infections and preventing abnormal cell growth), a happy set of neurotransmitters (the brain chemicals that control mood, energy, sleep, and focus), a highly functional digestive system, and a stable set of hormones (indicating healthy function of the thyroid, pancreas, ovaries, testes, and adrenal glands).

Editor’s note: For more great information on how to manage your cortisol levels, go to naturalsolutionsmag.com and type “cortisol” in the search bar. Be sure to check out the “Meditation 101” and “Adrenal Burnout” articles for practical suggestions.


Donielle Wilson, ND, CPM, is a graduate of Bastyr University and specializes in women’s health issues, specifically menopause, natural hormones, and integrative gynecology. A popular speaker and author, she is also the creator of the Hamptons Cleanse. You can visit her online at doctordoni.com.