Understanding Cortisol Dynamics

Cortisol, one of the primary stress hormones, has many responsibilities in the body. Among its vital functions are immune modulation, glycemic control and cardiovascular activity, including regulating blood pressure. It even affects digestion and the body’s utilization of proteins, carbohydrates, and fats.

To understand cortisol it is vital to remember that it increases in response to any stress in the body. The stress can be physical — such as illness, trauma, surgery, temperature extremes or inflammation — or psychological, brought on by financial problems, a poor marriage, the death of someone close, and so on. Neurological or biochemical imbalances are also a common type of stress.

Here is another important point: Although cortisol is produced by our adrenal glands in response to real and perceived threats, and therefore seems beyond our control, cortisol secretion is a learned response. If we experience the same occurrence over and over, cortisol mobilizes at that particular time in our daily biological rhythm (called a “circadian”) even in the absence of the original stimulus. Interestingly, a positive experience routinely causes cortisol levels to elevate for a period of approximately 15 minutes before it rebounds. However, a negative interaction, such as an argument, causes cortisol levels to drop for a period of approximately six hours.

One of the great advantages of salivary hormone testing is that it allows an individual to test within their personal environment, following their usual 24-hour routine. Saliva is collected in small tubes every four hours (8 AM, noon, 4 PM, 8 PM, midnight and 4 AM) and samples put in the freezer before sending them in to the lab. (By contrast, taking time out of our normal day, getting into a car and fighting traffic to get to a lab to have our blood drawn can cause anyone’s stress hormones to spike!)

When analyzing the 24-hour circadian, each increment can be indicative of the system involved in generating the stress. With this in mind, the pattern becomes more important than the ranges.

This is a vital point: One must not only measure hormones quantitatively, i.e., the amounts found in saliva (or urine or blood). You must also look at the ratios between various hormones, as well as the dynamic changes throughout the 24-hour circadian. The relationships among hormones are more informative than their individual measurements.

Moreover, my research has indicated that each event -- that is, either an elevation in cortisol or a decrease — is reflective of where the stress is originating. This is why salivary hormone testing is so valuable.

As I mentioned, cortisol responds to specific events. It is very important to look at the fluctuations, even if they appear to be within normal ranges. Some of the patterns that I have observed indicate that, for example, the cortisol level at 8am gives insight into the size and status of the adrenal glands. If the adrenals are enlarged there will be a high output at this time. If the adrenals are atrophied (shrinking) then the level of cortisol will be low.

The drop from 8am to noon is a dynamic change that can indicate an inflammatory process. Usually a drop of 50% or more is associated with the digestive system. A drop in excess of 70% is usually a parasitic infestation.

The measurement at noon is especially reflective of glycemic control. The levels at 4pm give insight into chronic infections. Usually elevations are associated with bacterial overgrowth, and suboptimal values are associated with viral infections. Cortisol levels at 8pm are associated with the utilization of insulin, and can indicate insulin resistance or type 2 diabetes. The midnight measurement is important, because if cortisol is elevated it can interfere with the release of growth hormone and also proper immune modulation. Spiking at 4am is an abnormal elevation that reflects the blood sugar reserves have run out: Cortisol elevates to bring the blood sugar back into normal range.

DHEA-S plays an essential role in the cortisol dynamics and it needs to be measured throughout the 24-hour circadian as well. DHEA is a hormone precursor — a substance that the body uses to make other hormones. Comparing DHEA-S patterns to cortisol’s provides confirmation that out-of-range readings are not caused by error or artifact, and also contributes its own indications as to which biological systems are involved and to what extent.

Thus, properly interpreted 24-hour salivary testing not only provides a tremendous amount of information on hormones: It can also show how the endocrine system is affecting and being affected by other parts of the body and, as such, is an invaluable tool for holistic medicine.