Stress is a part of everyday life, and so is the cascade of cortisol that can come with it. Everything from a work email to a tough workout to an argument with a family member can cause your cortisol to spike temporarily. This is normal. But when your body is exposed to too much stress for too long, the stress response stays switched on instead of settling back down, which can throw your hormones out of balance and contribute to health issues over time. 

This doesn’t mean cortisol is all bad. Cortisol, often called the “stress hormone,” is necessary for your body to function: it increases naturally early in the morning even before we rise and peaks soon after we wake; rises with certain kinds of exercise; and helps prevent hypoglycemia (low blood sugar) during fasting and while we sleep. Learning to manage stress can help your body understand what’s a threat, what’s not, and how to keep your cortisol in check.

What is cortisol?

Cortisol is a steroid hormone produced by the body’s adrenal glands, which sit on top of the kidneys. It interacts with almost every organ and tissue in the body, and it follows a daily rhythm, typically reaching its peak in the morning and falling at night to allow the body to sleep. This pattern is part of what is known as your circadian rhythm, and it affects your sleep schedule, when you eat, and your overall energy.  

Why is cortisol important?

Cortisol also serves many other important functions.  

  • It impacts your body’s response to stress: This is the most classic cortisol function. “When we’re stressed, the body will make more cortisol as a response to whatever the stress is,” explains Peter Bongiorno, ND, LAc, an integrative medicine specialist and expert in mental health at the Atria Health and Research Institute. “It also releases glucose (sugar) to give us energy and ready the brain for fighting or running or whatever we need to do in a stressful situation.”
  • It helps regulate your metabolism: It controls blood sugar and insulin levels to maintain energy throughout the day.
  • It can reduce inflammation: In normal amounts, cortisol prevents your immune system from overreacting, thus limiting inflammation.
  • It helps regulate blood pressure: Cortisol helps ensure blood vessels respond to adrenaline and keeps blood pressure from getting too low. Too little cortisol can cause dangerously low blood pressure, while chronic excess cortisol can raise it.
  • It supports memory and attention: Cortisol sharpens alertness and helps the brain encode important memories. When levels stay high for long periods, the effect reverses, and memory, attention, and executive functioning can suffer.

What happens when cortisol is too high or too low? 

It’s normal for cortisol to rise in response to everyday activities. Issues can arise, however, when cortisol gets stuck in an elevated position, whether due to a particularly traumatic event, or due to accumulated stress over time. “We live really stressful lives,” says Bongiorno. “It’s not always one event, but a lot of events that keep coming, and as one goes away, the next one’s still coming in, and our stress levels remain high.”

When cortisol stays high for too long, it can weaken the immune system, leaving you vulnerable to infections, disrupting sleep, causing high blood pressure and high blood sugar, weakening bones and increasing the risk of osteoporosis, and impairing brain functions including memory, attention, and learning. If cortisol levels are persistently elevated, it can be a sign of Cushing syndrome, a rare condition your physician can evaluate. In contrast, consistently low cortisol can cause symptoms including weight loss, fatigue, dizziness, low blood sugar, and nausea, as seen in adrenal insufficiency or Addison’s disease.

Your doctor can test your levels, ideally using a 24-hour urine test that will measure cortisol over the course of a day or a salivary cortisol test to examine your cortisol rhythm. Not every meaningful change in cortisol shows up as a diagnosable disease, Bongiorno says. And because factors like genetics, sleep, lifestyle, and even how much control you feel over your stress all shape cortisol, the same stressful situation can affect two people's cortisol very differently. “Let’s say you’re under chronic stress, but you’re getting sleep regularly, you’re exercising, eating healthy foods, and drinking enough water—you’ve already built in ways to create resilience and deal with cortisol,” he says.

How to keep cortisol levels healthy

Resilience is a big part of why lifestyle strategies are key for keeping cortisol levels in check. 

Consistent exercise, in particular, helps your body regulate cortisol by essentially stress-testing its stress response. An intense workout raises cortisol in the moment, and that increase is temporary and helpful. Seeing these spikes on a regular basis teaches your body how to bring cortisol levels back to a healthy level and helps it adapt over time. 

Research also suggests that mind-body practices like yoga and qigong can help reduce stress and lower cortisol levels. Controlled breathing exercises and spending time in nature have also been shown to help. (For expert-supported breathing techniques, see this primer.)

Bongiorno says there are also many strategies in the world of natural medicine that he finds useful. When cortisol is significantly dysregulated, he often turns to adaptogens, a group of herbs traditionally used to help the body cope with stress. The best studied is ashwagandha, a shrub traditionally used in Ayurvedic medicine that has been shown in several small randomized trials to lower cortisol modestly and, in some studies, to reduce perceived stress and anxiety. “The goal is to help the stress response settle back toward normal rather than staying stuck on high,” Bongiorno says. He cautions that adaptogens are not a treatment for genuinely low cortisol, which requires medical evaluation, and that any new herb or supplement should be started in collaboration with your health care team rather than picked up at the health food store. Ashwagandha in particular can interact with thyroid medication, has been linked to cases of liver injury, and should be avoided in pregnancy.  

Bongiorno notes there are a handful of other supplements he’s used with patients, depending on their specific stressors and needs. Of course, always talk with your doctor before starting any new supplement. 

Ultimately, Bongiorno notes that while supplements may help in some circumstances, maintaining healthy cortisol long-term requires addressing the underlying stressors. This can mean psychotherapy, including cognitive behavioral therapy, as well as meditation, and mindfulness. For people who have post-traumatic stress disorder (PTSD), a technique known as eye movement desensitization and reprocessing therapy, or EMDR, can work on processing the original trauma, though researchers are still working out exactly how it works. Others may find it useful to track their heart rate variability during breathing exercises, or try vagal nerve stimulation, which can send signals to the brain to help calm stress in the body.

The bottom line

Cortisol is a necessary hormone that rises and falls throughout the day, and a temporary spike after a stressful event or a workout is part of how the body adapts. The goal is helping cortisol return to baseline rather than eliminating those changes. Consistent sleep, regular exercise, nutritious food, mind-body practices, and mental health support build the resilience that keeps everyday stressors from piling up. Supplements may offer additional support for some people, though it’s always best to work with your care team to find the strategies that make sense for you.