Do Hard Workouts Raise Cortisol? Why the "Stress Hormone" Isn't Always Bad

You may have heard people online say that hard exercise is bad for you because it raises a hormone called cortisol. Some wellness influencers claim this 'stress hormone' causes a puffy face and extra belly fat. But scientists say those claims are mostly wrong. Experts explain that cortisol is actually a normal and important part of how your body works — and that exercise usually helps, not hurts.

Cortisol is made by small glands sitting on top of your kidneys called the adrenal glands. When your body feels stress, these glands release cortisol to help you react quickly. This is called the 'fight-or-flight' response, which gives you a burst of energy when you need it most. Cortisol also helps your body fight infections, control your heart rate and blood pressure, manage blood sugar, and regulate your sleep cycle.

Dr. Lena Fan is a hormone specialist and professor at the Icahn School of Medicine at Mount Sinai. She said to think of it this way: if you were being chased and needed to run, cortisol would help your muscles work harder and faster. Without it, your body wouldn't know how to handle dangerous or stressful situations. Cortisol is not the enemy — it is a tool your body depends on every day.

Even though social media makes it sound like high cortisol is very common, Dr. Fan says cortisol disorders are actually rare. Only about 1 in 100 people have cortisol levels that go above the normal range. Even people who deal with a lot of stress or anxiety usually stay within healthy cortisol levels. Most of what you see online about 'cortisol problems' is exaggerated or simply not backed by science.

When you exercise, your body releases more cortisol to help deliver oxygen to your muscles. Anthony Hackney, a professor of exercise science at the University of North Carolina, says this is a good thing. The harder you work out, the more cortisol your body releases to keep up with your muscles' needs. After you rest and eat, your cortisol drops back down — and it often ends up lower than before you started.

The key to getting these benefits is eating enough food and giving your body time to recover. Dr. Marie Schaefer, a sports medicine expert at the Cleveland Clinic, says that if you work out hard but don't eat enough carbohydrates, your cortisol may stay high for longer than it should. Doing too much exercise without enough rest — called overtraining — can also cancel out the stress-lowering benefits of working out. So eating well and resting are just as important as the workout itself.