How Does Exercise Affect Cortisol Levels?

The word "stress" just brings up bad vibes, right? So, it makes sense that cortisol—aka the "stress hormone" — would have a bad reputation. Exercise can even have an impact on the hormone, so it's important to learn the best exercise to reduce cortisol.

It's good to also note that, "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."

You may be wondering if your favorite workout, like running, increases cortisol. It is true that 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 all the details on cortisol, its relationship to exercise, and what you need to know about keeping yours in check.

What Is Cortisol?

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.

When Cortisol Becomes a Problem

To understand how, why, and when cortisol can become a problem, first think about how different our life stressors are now compared to 2 million years ago.

"In Paleolithic times, cortisol played a very helpful role in times of 'fight-or-flight' from an enemy or animal," explains Morgan Nolte, D.P.T., a board-certified clinical specialist in geriatric physical therapy in Omaha, Nebraska. The human body has evolved so that cortisol levels spike for a short period of time when you're in danger and then return to normal once the stressor disappears, she explains. This spike of cortisol was a good thing, giving you the extra boost of energy you needed to flee or put up a fight.

Flash-forward to the 21st century, and we may not be facing the "stress" of lions, tigers, and bears (oh my), but we're experiencing other (and way more) stressors that cause a cortisol response in the body.

"In general, modern stress is a different beast compared to the type and amount of stress the body has evolved to deal with," says Molloy. Nowadays, people are almost always under stress at work, he says, and then there's all the "little" stressors of everyday life like a passive-aggressive slack message, an ex watching your IG story, a troll on Twitter, an email with no exclamation marks, train delays, traffic, etc. that also cause a cortisol response in the body.

Unfortunately, "our bodies haven't evolved or adapted to the amount of stress we're constantly throwing at them," says Dr. Christofides. "So our stress response is constantly telling our systems that we're under attack, even when that 'attack' is just the go-go-go pace of everyday life."

For example, you might have a natural cortisol increase before a CrossFit competition or work presentation. Again, this is still a typically good thing because a brief spike in cortisol is associated with benefits such as improved memory and a higher pain threshold.

But because most people are experiencing more instances of stress more frequently than ever before, "sometimes your cortisol levels get out of whack," says Molloy. And that's when cortisol can become a problem.

Sometimes wonky cortisol levels are caused by a nodule in the adrenal gland, triggering it to make too much cortisol (known as Cushing syndrome), or adrenal gland making too little cortisol (known either as adrenal insufficiency or Addison's Disease), adds Nolte. But these aren't the cortisol issues most people are facing. Typically, the issue is excess stress.

How Exercise Affects Your Cortisol Levels

Remember how Malloy said that a stress responses can be triggered by emotional, mental, or physical stimuli? Well, if you've ever been through a break-up, gotten in a fight with your Mom, or had an unreasonable school or work deadline, you probably understand emotional and mental stress. But do you know what counts physical stress? It can be anything from a muscle tear after a soccer game or an injury after a car accident to general fatigue, dehydration/malnutrition, or exercise, according to Dr. Christofides. Yep, exercise causes physical stress.

Don't read it wrong: Exercise isn't bad! What is bad is the high-stress culture. And if you're under a lot of mental/emotional stress, exercising can sometimes help because it forces your cortisol levels to spike, which can then lead cortisol levels to stabilize, explains Dr. Christofides. What comes up, must come down, right? Well, it doesn't always work like that.

Sometimes, exercise exacerbates pre-existing cortisol imbalances, she says. "Because exercise yields the body's stress response, when cortisol levels aren't in homeostasis, it can cause cortisol levels to just remain high," she says. This is especially likely if you exercise at the end of the day, for a long period of time, or at uber-high intensities. (See: Is Your Really Intense Workout Making You Sick?)

"If you work out at the end of the day when your cortisol levels are supposed to be on the decline, it can cause your cortisol levels to deviate from their circadian rhythm," says Molloy. Usually, it's a short-term deviation and your cortisol levels return to normal. But exercising at night can exacerbate preexisting cortisol issues, he explains. (That's why exercising in the morning can be part of the solution, but more on that below).

The population most at risk for cortisol imbalances are endurance exercisers, according to Dr. Christofides. That's because endurance exercise increases the amount of time your body is under physical stress, according to a study on the topic published in the journal Psychoneuroendocrinology. If you're biking or running for two to three hours a day a few times a week, that's a lot of time with elevated cortisol levels, she says. So for people who already ('already' being the key word here!) have messed up cortisol levels, due to a really stressful out-of-the-gym life or a preexisting condition, endurance training can exacerbate the issue. While this shouldn't scare you out of training for a marathon, it should encourage you to prioritize your emotional health, mental health, and recovery during training.

Molloy says he also sees cortisol problems in communities of people who consistently perform strenuous workouts such as HIIT and CrossFit. "If you're going through a break-up, divorce, or crunch-time at work, you probably don't want to be doing a workout that's landing you flat on your back," he says. That's because, during these high-stress periods, your cortisol levels are already way up. So if a workout is leaving you flat, it probably spiked your cortisol levels even higher. Doing a workout that's going to majorly spike your cortisol levels when you're at a high-stress period of life is like trying to put out a fire with fuel—it makes the situation worse.

Symptoms and Side Effects of Cortisol Imbalance

If you love your current workout routine, the thought of dialing it back may sound counterintuitive, but "the cost of working out at 100 percent when your mental and emotional stress levels are at 100 percent is compromised muscle mass, strength plateaus, weight gain, and generalized exhaustion," says Molloy of the side effects of cortisol imbalance.

There are other non-exercise related symptoms, too—most of which are similar to the symptoms of overtraining syndrome. Some other symptoms of a cortisol imbalance are:

Because the whole endocrine system is interconnected, this is just the tip of the iceberg, says Len Lopez D.C., a chiropractor and fitness expert. For example, "your body needs progesterone to make cortisol. When there's an overproduction of cortisol, it can cause an imbalance in your progesterone and estrogen levels, which can lead to estrogen dominance," he says. (That in itself can lead to a number of other health issues such as obesity, cardiometabolic diseases, and even cancer.)

It's also worth mentioning that mental health issues like anxiety and depression have a direct relationship with cortisol. Some studies have linked heightened cortisol levels with mental health issues, while others have found that chronically elevated cortisol levels increase your risk for mental illness in the future.

Because, again, cortisol touches every single system in the body, chronically elevated cortisol levels can lead to other scary health issues such as cardiovascular disease and diabetes.

What to Do If You Think Your Cortisol Levels Are Off

If you think you're experiencing a cortisol imbalance, it's a good idea to chat with an endocrinologist. If that's indeed the case, there's good news: You probably don't have to stop working out completely. Instead, you may have to make some adjustments to both to your gym and out-of-the-gym routines.

For starters, try going to the gym in the morning. This will align your exercise-induced cortisol surge with the surge that happens naturally, explains Dr. Christofides. "Just don't go to the gym in the morning in place of sleeping a full seven to eight hours. That's the number one way to make this worse," she says.

If you're an ultra-marathoner or self-identified Cardio Bunny, you may need to schedule in an off-season where you're *not* logging too many miles. Or, you may simply need to incorporate more low-intensity weight training or yoga into your routine.

What if high-intensity exercise is your jam? Good news: "I would never say to stop doing CrossFit or HIIT," says Adam Splaver, M.D., cardiologist (and passionate CrossFitter) with The Doctor's Dr. This kind of exercise is tremendously beneficial, he adds. (FYI: Check out more on the health benefits of CrossFit and the health benefits of high-intensity interval training.)

The trick isn't to cancel your box or HIIT studio membership, but rather to go less often or work out at a lesser intensity. Molloy is a fan of the former: "If you're stressed, try performing these workouts at 70-85 percent of your max intensity."

Of course, "it's almost impossible to prescribe an exact workout regime that would reduce the risk of this because it's so individual," says Dr. Splaver. What's important, he says, is to tune into (and then listen to) your body.

From there, a few lifestyle changes can go a long way in balancing your cortisol levels:

"It's amazing what a difference journaling for three minutes before bed can do for your overall stress levels," says Molloy.

How Long Until Your Cortisol Levels Return to Normal?

"You can see some real differences within one or two weeks," says Molloy. "But it all comes down to how out-of-whack your cortisol levels are and how much you're able to change your lifestyle to address them." And of course, continuing to manage your stress levels is key to keeping them from spiking too high again, he says.

If you think your cortisol levels are doing something wonky, head to your healthcare provider to chat about solutions. And even if you're not convinced your cortisol levels are off, your health and wellness routine could probably benefit from the aforementioned lifestyle changes.