Edited by Kate Findley and proofread by Angela Shoemaker, The Great Courses Daily
Cortisol, known as the stress hormone, is often blamed for weight gain and poor health. Many half-true headlines add to the confusion. Professor Ormsbee investigates whether this association is a myth or the truth.
The Truth about Cortisol
In reality, the stress hormone cortisol is actually very important to our overall health. It helps our bodies have a healthy response to physical stressors, as well as life stressors such as crying children, deadlines, and traffic.
Cortisol is produced and released from the adrenal glands as part of a complex pathway known as the hypothalamic-pituitary-adrenal axis, or HPA axis. Cortisol and several other hormones are released according to the circadian rhythm of our bodies.
This means that the release of the hormones follows a pattern based on what time of day it is. Cortisol levels are highest in the morning in order to help with wakefulness, and to help provide energy after the overnight fast. Levels are lowest at night, allowing for rest and recovery.
The cortisol that is released in response to normal daily patterns, or due to stress, is actually very useful for us metabolically. It helps us to use our stored glucose, fat, and protein as energy to deal with the stresses we encounter or perceive to exist. Additionally, cortisol can temporarily improve brain and immune function to help us overcome a fear, meet a deadline, or try new exercises.
Cortisol Response to Stress
Cortisol also helps to decrease inflammation, which is why cortisone shots are used for treatment of inflammation in our joints. We get cortisone injections in knees, wrists, and other problematic areas as we age. In fact, certain autoimmune disorders like rheumatoid arthritis have been linked to suppressed HPA-axis activity and chronically low cortisol levels.
Cortisol has been observed to act quickly. After roughly 30 minutes, it will begin to degrade and the HPA axis will stop releasing it.
Thus, the cortisol response to an acute stress like exercise is really long and quite useful. Also, cortisol is going to be produced in your body, so even in a theoretical stress-free environment you would still produce cortisol according to that circadian rhythm. In fact, if you had chronically low cortisol concentrations, there’s a good chance you would feel uncomfortably tired and weak.
You may be wondering, then, how would your cortisol level become chronically elevated and whether it is making you store fat. In the nutrition and fitness world, the perception is that high cortisol equals high body fat.
In extreme clinical cases such as Cushing’s disease, where cortisol is very high all the time, fat gain is typically seen in the belly, abdomen, face, and neck. In addition, with chronically high cortisol levels, muscle can be broken down to provide energy. Over time, this leads to less muscle and more fat.
What Leads to Weight Gain
In short, high levels of cortisol over a long time can lead to fat storage, particularly in your visceral fat—the fat surrounding your organs. Chronically high cortisol is also linked to psychological factors like depression, anxiety, and grief, and to physical factors like extreme levels of exercise combined with little rest and recovery.
In these situations, not only are changes in your metabolism occurring, but your immune system may also become weak. This is why many people associate high stress or extreme exercise over a long period of time with greater occurrence of sickness.
Even though exercise and other stressors can temporarily increase cortisol, and cortisol in chronically elevated situations is associated with fat storage, any change in body weight or body fat is probably due to the fact that many people deal with these stresses by eating more and making poor food choices. Thus, don’t shy away from physical activity.
Normal levels of exercise are not likely to cause chronically high levels of cortisol. In fact, exercise for about an hour a day should help keep cortisol levels within normal ranges.
The point is that cortisol must be present in your body. It is extremely helpful metabolically, and even if you are completely stress-free, your cortisol values won’t drop dramatically. The issues with cortisol happen when cortisol is chronically elevated.
This article was edited by Kate Findley, Writer for The Great Courses Daily, and proofread by Angela Shoemaker, Proofreader and Copy Editor for The Great Courses Daily.
Michael Ormsbee is an Associate Professor in the Department of Nutrition, Food, and Exercise Sciences and Interim Director of the Institute of Sports Sciences and Medicine in the College of Human Sciences at Florida State University. He received his MS in Exercise Physiology from South Dakota State University and his PhD in Bioenergetics from East Carolina University.