Cortisol: Everything You Need To Know About This Undervalued Hormone

What is cortisol? 

That’s probably the question you asked yourself when you clicked on this article.

No, it is not some new topical ointment that relieves an itch, that’s Cortizone.

Cortisol is the most misunderstood hormone in the human body. While everyone knows it as the dreaded fat-storing hormone, it actually does a lot of critical things that help our bodies function every single day. 

So many that I took to my friend and expert on all things hormones, Dr. Stefania Tiveron, to step in and preach more about the importance of cortisol, what it does to our bodies, and how we can improve our levels of it!

Take it away Stefania….

**Stefania is typing now***

For many in the health industry, Cortisol is known as the body’s “fat-storing” stress hormone. 

Though widely accepted by most, this definition is incomplete. Matter of fact, I’d argue that definition gives cortisol a bad reputation, by implying that cortisol has one devious job: to make us store fat. 

That’s far from the truth.

A simple explanation of cortisol…

Like all hormones, cortisol is a messenger.

Cortisol is derived from cholesterol and made/released by the adrenal glands. It supports many functions in the human body, such as mediating the stress response, regulating metabolism, the inflammatory response, and immune function. 

When properly regulated within the body, the production and secretion of cortisol are also protective of these systems. 

All that said, it’s not inherently bad! You wouldn’t want to shoot the messenger, right? 

How cortisol works in our bodies…

Stress is the name of the game when we’re talking cortisol. The more stress in, the higher the cortisol; the less stress, the lower.

Here’s how it works:

  • First, we encounter a stressor of any kind. The brain then sends a signal to the adrenals to release cortisol. 
  • From there, cortisol’s metabolic effects provide energy to the body, which allows the body to continue to stay on high alert. 
  • Once the stressor passes, the brain sends another signal to the adrenals to stop releasing cortisol. 
  • Under this type of regulation, the body returns to a state of “homeostasis” or balance.

What causes the release of cortisol?

Before we can start addressing our cortisol levels, we need to understand where the triggers that elevate this hormone come from. Luckily, both are very simple… 

  • Physiological Stress: Cortisol is released to help us manage stress. We are able to mobilize resources for today’s performance, but only for short periods of time. It’s like using a credit card to temporarily spend more money than you have—possible, but not sustainable.
  • Circadian Rhythm: Higher circulating cortisol levels are observed during the early morning, with lower levels evident around midnight.

We’ve already covered the impact physiological stress can have on our cortisol levels, so let’s look at the diurnal (daily) rhythm of cortisol in the context of our sleep. 

The secretion of cortisol follows an internal 24-hour clock that regulates our sleep-wake cycle. 

In normal sleep-wake cycles, a surge in secretion is seen between 4 am and 8 am with declining levels throughout the day, the lowest of which is seen just after midnight. Melatonin starts to spike around bedtime, which initiates a feeling of sleepiness. 

Note: We do have “bursts” of secretion throughout the day (roughly 10-18 bursts per 24-hour period). 

Knowing this, we can clearly see that too much stress throughout the day elevates cortisol levels, which can remain elevated at night, causing insomnia or poor sleep. 

Cortisol effects in real-life…

I always find it helpful to put examples of what we’re talking about so you can see how it applies to everyday life. Luckily, we’ve got Coach Ann who’s shared a recent stress test with us!

A stress test is a functional assessment that evaluates salivary levels of cortisol throughout an entire day. This type of testing helps uncover disruptions in circadian patterns, especially when there are issues with sleep, waking up, and energy.

Looking at the shaded green area on the graph—which represents the normal range for healthy adults—we can see that Ann’s cortisol levels follow an appropriate diurnal (daily) rhythm during the day, with a very robust burst of cortisol in the morning.

If you look toward the right, you’ll see the point at which her cortisol levels should be naturally declining, and instead, we see a spike.

What could that be?

Maybe this pattern correlated with her increased workload in the evening, resulting in sub-optimal sleep.

If you had asked Ann at the time, she would probably tell you she was feeling more stressed than usual—and she certainly noticed the effects on her sleep and energy levels. 

What does this mean?

In Ann’s case, we see an adaptive and appropriate response from cortisol.

During this period, the effects of cortisol allowed Ann to move forward during the day, but higher levels of cortisol in the evening suppressed her ability to feel sleepy at night.

Cortisol’s message was clear: Give her energy. Mobilize resources. Use credit if you need to

As far as Ann’s brain understood, she was stressed. She needed that cortisol to manage an increased workload and that likely worked for that period of time.

But is that sustainable? 

What impact do high levels of cortisol have on the body?

As we talked about before, cortisol is great when we need that quick boost of energy to combat a stressor, but when we rely on it 24/7 to solve the problem, we can quickly watch our health stumble. 

When the human body is exposed to high cortisol levels for an extended period of time it grinds our systems down, exceeding healthy normal limits, and leading to exhaustion.

Think of it like this… 

If you started weight training right now, and then never stopped, what would happen to your body? 

Exercise is a physical stressor—we engage in exercise for many reasons, such as fat loss, muscle growth, stronger bones, endurance, etc. 

These beneficial “side effects” are adaptive responses. When we rest between physical training sessions, our body adapts in order to better handle similar future physical stressors (ie. your next training session). Your muscles become stronger and larger as a result of weight training.

But here’s the caveat…

It adapts under conditions of rest, not when we train! 

Physiological stress, due to exercise or other reasons, initiates a cascade of signals to engage the body and mobilize its resources for continual performance. Cortisol, of course, is part of that cascade. 

If followed up with rest and recovery, cortisol levels return to baseline pre-stress levels and the body has the opportunity and resources to adapt. When the stress arises again, the body is primed to respond in ways it already knows to protect itself! 

Under the right conditions and appropriate regulation, this stress actually builds resiliency. 

How to manage your cortisol levels better…

We all have triggers for stress in our daily lives, even desirable ones that provoke a sense of excitement and anxiety. When regulated, the effects of cortisol are protective and helpful. 

The key to keeping cortisol levels in the appropriate healthy range is simple, but not easy. Here are some helpful tips to manage it:

  • Do not overdraw on your resources. 
  • Balance periods of stress with periods of rest. 
  • Honor the natural daily rhythm of cortisol by tapering stimulating activities as the day goes on. 
  • Create an evening transition or wind-down routine that supports the natural decline in cortisol, while simultaneously supporting the natural increase in melatonin levels. 

Remember, awareness is key! 

Closely monitor your stress triggers and how you respond to them. When overwhelmed and exhausted, the stress response system can create a disproportionate reaction. 

Ever hear someone say, “the straw that broke the camel’s back”. Sometimes it’s the littlest of things that break us down because we overdrew for too long. The same goes for stress. 

Regular and intentional periods of rest and relaxation are like payments to the stress response system. Think about how you can make daily payments to keep your system topped up for a rainy day! 

Cortisol Recap

  • Physiological Stress = increased production and release of cortisol to mobilize resources to buffer stressors. 
  • Rest & Recovery = protective adaptations that make the stress response system stronger and more resilient. 
  • Results = Better response when/if the stress arises again. 

Ann and I will be coming to you with more science-backed stories over the coming weeks so stay tuned to her newsletter for my next article! 

Dr. Stefania