Hormone Response To Exercise: Cortisol

By Shelby Stoner, PHASE IV Exercise Physiologist

Previous articles in the Hormone Series:

Hormone Response To Exercise: Insulin

Hormone Response To Exercise:  HGH

Hormone Response To Exercise: Ghrelin

Hormone Response to Exercise: Leptin



Cortisol is a steroid hormone that is released into the bloodstream by the adrenal glands and plays an important role in carbohydrate, protein and fat metabolism in the body. More specifically, cortisol stimulates gluconeogenesis, which is the fancy way of referring to the conversion of noncarbohydrate sources (usually in the form of amino acids) into carbohydrate within the liver. It also helps facilitate fat breakdown, allowing fatty acids to enter the bloodstream and be used for fuel. This is important because by freeing up fatty acids for metabolic fuel, our precious glucose stores are spared for feeding the brain.

Another primary role of cortisol is serving as one of the body’s stress hormones, released as part of the fight-or-flight response. An example of this includes shutting down less critical functions like reproduction and immunity to focus on fighting immediate physical threats. These particular functions of cortisol are supposed to be immediate and short lived, just enough to see off any physical challenge. This may have been great back in the day for cavemen fighting for their lives-but less ideal in modern times when stress can be psychological and consistent.


Cortisol has a vital physiological role. By raising plasma glucose levels at times of stress, cortisol provides the body with the energy it needs to face bodily attacks from injury, illness or infection. However, too much cortisol for too long can have serious, negative effects. The tissue breakdown, reduced protein synthesis and conversion of protein to glucose can decrease musculature and increase abdominal fat, not an ideal result! In addition, excess cortisol levels decrease the usage of glucose and increases blood levels where in more serious cases can lead to diabetes. With this in mind, it is important to make sure we are actively controlling our circulating cortisol levels for optimal health and well-being.


Exercise is perceived as a form of stress by the body which stimulates the release of cortisol. In general, as your fitness improves, the better your body is at handling and dealing with the physical stress. As a result, less cortisol will be released during exercise and in response to other emotional or psychological stresses.

It’s important to remember that the TIME and INTENSITY of exercise can affect levels of cortisol release. When it comes to exercise, more may not be better.


Although exercise is considered a stressor and raises cortisol levels in the body, it is possible to enjoy the benefits of exercise without skyrocketing cortisol concentrations and wreaking havoc on our metabolisms. Following these general guidelines can help ensure you’re reaping the benefits of your training without over-doing it:

  • Incorporate proper recovery into your training regimen. Take regular breaks from intense training and listen to your body. Proper recovery determines strength gains and weight loss, the physical adaptations we all seek. Not to mention, it prevents burnout and fitness plateaus. Make sure you are getting at least one FULL day recovery each week, with active recovery after hard workouts to help promote blood flow to the muscle and eliminate toxins.
  • Eat right to fuel your body and workouts. Check out this article to learn more about this.
  • Follow the hard/easy principle. The principle states that one or two days of hard training should be followed by one day of soft or easy training, which allows the body and mind to fully recover and prevent overtraining. The hard / easy principle is a crucial component of all periodized training programs. Periodization is the gradual cycling of specificity, intensity and volume of training in order to achieve peak levels of fitness.
  • Sleep! It’s our body’s natural way of recovering. All of your hard work towards reaching your goals will be unproductive if you aren’t getting enough sleep. Getting at least 7-8 hours of sleep each night helps control the release of hunger hormones and allows the body to detoxify. This helps curb harmful inflammation in the body that leads to heart disease, stroke, diabetes, and many other health conditions. Make it a habit to get to bed by 10 pm each night, and away from distractions. Replace technology with breathing techniques and other forms of relaxation in order to help reduce stress.

Whether your goals are related to weight loss or improved performance, PHASE IV science has the answers. Call us to schedule a complimentary 30-minute health and fitness consultation at our facility in Santa Monica. 310-582-8212

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