What Cortisol Does and How It Works
Cortisol is a hormone produced in the adrenal glands, released into the blood, and transported all throughout the body as it responds to stress. Almost every cell has a cortisol receptor, which means that nearly every organ system can be affected by cortisol. It’s kind of a big deal.
Cortisol works with certain parts of your brain to control your mood, motivation, and fear. When balanced, cortisol enhances activeness, alertness, and relaxation, and reduces stress and nervousness.
Your blood levels of cortisol naturally rise and fall throughout the day, but tend to be higher in the morning when you wake up, and then fall throughout the day. This is called a diurnal rhythm.
If your cortisol is operating as it should, cortisol levels typically reach their lowest levels late at night—usually around midnight—setting your body up for deep REM sleep. From there, levels begin to rise. Cortisol reaches its highest level in the body early in the morning to help your body get up and running—peaking around 8am— before declining throughout the day.
Diseases, irregular work shifts, or sleeping a lot during the day can disrupt the normal pattern, but the most common disruption of a diurnal rhythm and optimum cortisol production is stress.
The key is to get your body on its ideal cortisol level “schedule” with optimal amounts of cortisol, ebbing and flowing, at the appropriate times of the day. This is called your circadian rhythm (we’ll get into this…just know it’s not a latin dance move).
When cortisol levels are too high for too long, it can cause the suppression of testosterone and human growth hormone (hGH). In fact, cortisol can be a sort of “enemy” to testosterone, especially when you benefit from keeping testosterone and other protective hormones high. (And yes, women need testosterone too.)
When cortisol is too high, your body cannot produce enough enzyme 11βHSD-1 (we know that’s a mouthful) to counteract the cortisol, leaving you with a surplus of the stress hormone and the destruction of any freshly-made testosterone. In the same vein, it can inhibit the production of hGH, which is essential for building muscle, exercise and illness recovery, a well-functioning metabolism, healthy skin, hair, and nails, cellular repair, and overall maintaining a sense of youthfulness in all dimensions.
— ALISON GRACOM, PA-C & ENDOCRINOLOGY EXPERT