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Cortisol Curve Collapse — Fatigue

Hormones affect every system in the body.

Cortisol, the adrenal hormone that helps the body manage stress, has impacts on nearly all the body systems. Cortisol levels naturally fluctuate throughout the day, normally peaking in the morning hours and bottoming out at night. Studies show that deviations from this pattern are associated with signs and symptoms of adrenal dysfunction.

Cortisol is the hormone which is responsible for helping you deal with stressors. Whether that stressor is physical (allergies, infection, cancer, trauma, lack of sleep, bad food choices, working out, etc.) or whether that stressor is psychological (work, relationships, finances, fear, etc.) the body has one response – Cortisol.

Cortisol is the strongest hormone in the body. The function of cortisol is to increase blood sugar levels so that you can run away from a dinosaur and to decrease inflammation so that you can continue to run away from that dinosaur. Cortisol breaks down muscle, bone, and even tissues like the brain in order to convert those tissues to sugar (which helps the body run away from the dinosaur!)

Animals use cortisol to get away from a danger, and once away from that danger, their cortisol levels return to normal. Our system was evolved to use cortisol only intermittently.

However, in prolonged exposure to any stressor with prolonged elevation of cortisol takes its toll on every system. Cortisol, with enough time, eventually breaks down the brain. A part of the brain called the hippocampus, which is responsible for memories of dangers, eventually gets “eaten away” by the cortisol. The brain, after time, has no other course than to tell the adrenal glands (which produce the cortisol) to decrease their function.

Now, instead of the cortisol peaking in the morning (generating energy for the body so that you can start your engine), the cortisol takes on a flat curve in which the amount of cortisol secreted does not change much throughout the day. In both seemingly healthy and clinical populations, a flattened cortisol curve has been robustly associated with shorter lifespan and negative health indicators.



Studies indicate that a flattened cortisol curve statistically predicted poor survival time in patients with metastatic breast cancer. Natural killer cell numbers and activity were also decreased. In these patients, 70% had flattened cortisol curves, presumably due to the physical and emotional stress of their diagnosis and treatment.

Flattening of the cortisol curve also has been shown to predict early death from lung cancer and has been associated with low T-cell lymphocyte counts.

In one study of healthy individuals, diurnal cortisol patterns were measured for 2 years and then participants were followed for 6 to 8 more years. Participants tended to be middle aged (average of 61 years), and flattened cortisol curves were correlated with mortality from all causes as well as cardiovascular deaths.

Measuring cortisol over the course of a day may predict health outcomes both for diagnosed and for seemingly healthy individuals. Understanding the mechanisms by which cortisol secretion can be changed in the body can inform appropriate treatment interventions. One interesting finding is that neighborhoods with more stressors are correlated with flattened cortisol curves for the populations who live there, suggesting that social status and cortisol curves may be related.

Cortisol levels are not measured well by blood tests. To accurately get a picture of what the levels of cortisol are throughout the day, a saliva test with samples taken 1 hour after awakening, before lunch, before dinner and before bed, is the best method to measure the cortisol curve.

Cortisol can also be measured well through dry urine samples obtained, similarly to the saliva test, at 4 times throughout the day. The advantage of the urine dry-spot testing is that we can also obtain all the metabolites of cortisol as well as the approximate total amount of cortisol produced throughout a day. Knowing the total amount of cortisol as well as what the levels are throughout the day, gives the clinician the best information about what your adrenal glands are doing in response to stress (whether acute or prolonged).

Treatment for high or low cortisol levels revolves around identifying the cause of the stress. A thorough history into stressors (both physical and psychological), lab tests for inflammation and immune function, nutrient evaluation (because the adrenals need nutrients to make cortisol) are but a few of the factors which your physician should use in determining the cause of the adrenal (cortisol) dysfunction.

Symptoms of abnormal cortisol levels are many and varied, but the most common symptoms presented by the patient (in order of their frequency) are:

  • Fatigue
  • Anxiety
  • Lack of focus
  • Depression
  • Sleep disturbance
  • Light-headedness
  • Muscle weakness and pain
  • Recurrent infections
  • Salt cravings
  • Excessive thirst
  • Urinating often and a lot


Traditional physicians rarely look at the cortisol curve. I know, I am trained as a traditional physician. Cortisol curves are a routine and important part of the evaluation of every patient in our practice.

There are excellent treatments to balance your cortisol levels and discover what is pushing your buttons!