The truth about the internet’s favourite stress hormone

“Cortisol is your friend,” Fricchione said, “until there’s too much of it.”

We function best when we have the right balance of cortisol. “Our bodies are this harmonic unit,” Fogelman said. But chronic stress can elevate our baseline cortisol levels over time, leading to a cascade of consequences. Persistently high cortisol levels may weaken the immune system, Fricchione said, as well as raise blood sugar levels and blood pressure. There’s also an integral link between cortisol and sleep: We need the hormone level to decrease so that we can fully rest. People with high cortisol often struggle to fall and stay asleep, Fricchione said.

Some mental health conditions, including depression and post-traumatic stress disorder, are associated with cortisol imbalances, said Dr. Raza Sagarwala, a resident physician in the department of psychiatry at Vanderbilt University Medical Centre who has studied the effects of non-pharmacological treatments on cortisol levels.

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Without testing cortisol levels and consulting a physician, it’s almost impossible to determine whether something like acne or poor sleep is definitively linked to hormone imbalances — and cortisol may just be a convenient culprit that people can point to when they don’t have any other clear explanations for their health concerns. “When people say they have elevated cortisol — I would tell you, you cannot feel that,” Bennett said. But if people are truly worried about their cortisol levels, experts said, they can talk to their primary care doctors about getting tested.

You can use blood or saliva to test your cortisol levels at a particular moment, but a one-time snapshot isn’t likely to be useful, Picard said, because cortisol levels change throughout the day. Urine or hair samples can reveal cortisol levels over a longer period of time, although hair samples are primarily used in research settings.

Some companies offer at-home cortisol tests, which typically involve finger pricks or saliva swabs. But experts instead recommend talking to a primary care doctor, who may refer you to an endocrinologist.

One reason for the caution is that physicians try to obtain a comprehensive picture of how your cortisol levels ebb and flow before determining whether there may be any issues, said Dr Mihail Zilbermint, an associate professor of clinical medicine specialising in endocrinology at Johns Hopkins Medicine. “It’s not hard to test cortisol levels, but it’s not easy to interpret,” he added.

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Some small studies have suggested that yoga and mindfulness interventions such as meditation may help lower cortisol levels, Sagarwala said.

Exercise can also be helpful for regulating cortisol, Bennett said, especially moderate physical activity such as jogging or cycling. Those movements prompt your body to mirror your stress response, raising your heart rate and then lowering it once you stop working out. That cycle effectively trains our bodies to activate and shut down our stress response appropriately.

People should identify stress reduction methods that work best for them, Fogelman said. A few minutes of box breathing, for example, might soothe one person but not another. Once you find a strategy for alleviating stress, your cortisol levels can become more stable, she added; this is true even for people who have been exposed to long-term stress.

“Stress is not a bad word,” Fricchione said. “Just being a living organism means that there’s going to be stress.”

This article originally appeared in The New York Times.

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