The word stress just brings up bad vibes, right? So, it makes sense that cortisol, “stress hormone” would have a bad reputation.

But “cortisol is not, in itself, bad—it’s just a hormone,” says Mike Molloy, Ph.D., founder of M2 Performance Nutrition, who’s studied microbiology and immunology. “But the dosage and amounts of cortisol in the body need to be right.”

And one of the things that can throw (or keep) your cortisol levels off is exercise—especially when the rest of your life is stressed out. But (!!) that doesn’t mean you should swear off sweating in the name of being stressed.

Scroll down for a crib sheet on cortisol, its relationship to exercise, and what you need to know about keeping yours in check.

What Is Cortisol, Anyway?

Cortisol may be nicknamed the “stress hormone,” but this steroid hormone does way more than that. In fact, “cortisol is the most important hormone in the body because it touches literally every other system in the body,” says board-certified endocrinologist Elena A. Christofides, M.D., F.A.C.E. It helps control blood sugar levels, regulates your metabolism and blood pressure, affects your sleep quality, impacts your sex life, assists with memory-making, and even aids in fetal health during pregnancy.

If your adrenal glands (which make cortisol and are located on top of your kidneys) were to be removed from your body, you would be dead within 24 hours—faster than if your thyroid or pancreas were removed, and both of which also produce hormones, she says.

Your cortisol levels are controlled by your pituitary glands, which are located in your brain. They use their spidey senses to tell if your blood has the “right” amount of cortisol. Too much or too little cortisol in the body? The pituitary glands tell the adrenal glands to adjust.

Generally, your cortisol levels follow a circadian rhythm, peaking in the morning and declining at the end of the day, according to Molloy. Of course, they can also fluctuate based on what you’re ~experiencing~. “Stress is anything that triggers the adrenal glands to produce more cortisol, so any stress (be it mental, emotional, or physical) can cause a cortisol response in the body,” he explains.