More about cortisol, the “stress hormone”

In a previous post, I wrote about two important hormones that affect weight loss – insulin and cortisol. In this article, I discuss cortisol in more depth: its relationship to the body’s stress response, and how it influences fat and protein metabolism and blood sugar levels.

Cortisol is considered the primary “stress hormone” because it’s released in response to perceived threats, or “stressors” along with adrenaline, which elevates heart rate and blood pressure. Our primitive ancestors’ survival depended on a “fight or flight” response to escape a saber-toothed tiger, and cortisol provides the body with additional glucose (blood sugar) needed for immediate energy to fight or flee that tiger. In our modern world, we’re not usually fleeing from real tigers – rather, from imagined ones. The idiot driver who’s tailgating you at 65 mph, the boss who gives you a project at 4:00PM and wants it done by 8:00AM tomorrow, the three-mile traffic jam when you’re already late, the incessant ringing/buzzing/chirping electronic devices, and so many other constant pressures of daily life, are what trigger our cortisol stress response.

Produced by the adrenal glands, cortisol is a glucocorticoid, meaning it is a steroid hormone. Steroid hormones are created from cholesterol and are lipid (fat) soluble. As a result, these types of hormones can easily move into almost every kind of body cell, because most cell membranes are also lipid-based. Cortisol’s far-reaching, systemic effects play many roles in the body’s effort to carry out its processes and maintain internal balance [1].

What’s also interesting is that high intensity exercise, with all its health benefits, can create a stress response that elevates cortisol levels detrimentally. I’ve observed many aerobics instructors over the years who carried a lot of excess body fat in their midsections. How could this be, when they’re teaching 5 to 10 or more exercise classes every week? The answer: high intensity exercise is a stressor on the body, and the body’s response is to release cortisol, which in turn causes lots of extra stored glucose to be released into the bloodstream. All that extra glucose, which isn’t really needed, is eventually stored as body fat – particularly in the midsection.

There’s a strong mind-body connection when it comes to cortisol. We certainly need that fight-or-flight response to a real threat (you’re about to miss your flight and have to run for the gate before they close the cabin doors) or even a self-imposed stressor like competing in a 10k race or a triathlon. It’s that chronic elevated cortisol from everyday life stressors that we should aim to reduce. Balanced nutrition, mind-body practices such as yoga, meditation, and mindfulness, or even just having a good laugh, can all help to reduce those imaginary tigers to kittens.

But what about exercise? We all know how exercise can reduce mental stress and elevate mood (using other hormones), but when it comes to high intensity workouts, there can be “too much of a good thing.”  Cortisol has been closely linked to exercise and overtraining syndrome. High intensity workouts, such as performing sprints or engaging in rigorous strength training workouts, have been correlated with increased blood cortisol concentrations [2].

So what’s a body to do? A balanced program of functional strength training, steady-state and high intensity cardio intervals – combined with stress-reducing mind/body practices, recovery, and good nutrition – seems to be the best way to effectively manage cortisol and its effects.

I’d love to help you develop a balanced program that reduces stress while getting you fit. Contact me today and let’s have a conversation!

Sources Quoted:

[1] Aronson, Dina MS, RD. Cortisol — Its Role in Stress, Inflammation, and Indications for Diet Therapy. Today’s Dietitian, Vol. 11 No. 11 [November 2009 Issue]

[2] Kronemer, Cathleen. Does Exercise Lower or Raise Cortisol Levels? National Association of Professional Trainers.

Other Sources:

Moini, Jahangir. Anatomy and Physiology for Health Professionals, Second Edition. Jones and Bartlett Learning, 2016.

Chronic Stress Puts Your Health at Risk.

Randall, Michael. The Physiology of Stress: Cortisol and the Hypothalamic-Pituitary-Adrenal Axis. Dartmouth Undergraduate Journal of Science. 3 February 2011.

Exercising to Relax. Harvard Medical School Harvard Health Publishing. February 2011.


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