Stress Test: What You Should Know About Cortisol

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Stress Test: What You Should Know About Cortisol

Stress Test is a series about the science behind our busy lives and how stress affects our bodies. The biweekly column uncovers the latest research and explains how to put it to use in a practical way. Look for the science behind epigenetic markers of stress, mindfulness, meditation and deep brain stimulation.


When it comes to stress, we often think of cortisol as a bad thing. It’s earned the reputation as a harmful hormone that boosts weight gain and slows us down. In reality, it’s just one type of hormone in our bodies – called a glucocorticoid – made by the adrenal glands. It regulates blood sugar, metabolism and stress.

Evolutionarily, cortisol is used to boost heart rate, elevate blood pressure and increase energy supplies during a stressful situation. Now that many people face stress consistently, however, ongoing high levels of the hormone can harm the body. In fact, it does more than cause weight gain and high blood pressure — it interferes with learning, memory and the immune system.

That’s why public health researchers have recently focused on cortisol and what we can do to use it for good in the body or reduce its harmful effects. In the past few months alone, scientists have released new thoughts about cortisol’s potential effects on caregiving, post traumatic stress disorder, and good habits.

Here’s what researchers can tell us about cortisol currently:

1. Cortisol Impacts Decisions

When we’re stressed, especially for long periods of time, it can break down our ability to make decisions quickly and decisively. When we’re faced with the decision to stick with the current option or try something new, stress often causes us to choose the current option for longer than we want, New York University professors concluded in early May. Could this be a relationship, job or even bad habit we’re unable to break?

At the same time, recent studies have found that cortisol may help emotional decision-making as well. German researchers published a study in early May, for example, that found acute stress may actually have prosocial and positive effects on moral decisions, particularly in young men. The group that underwent a well-known stress test tended to make altruistic (rather than egoistic) decisions and felt more positive and more certain about their decisions. It seems there’s an interesting balance in the decision-making effects of cortisol that scientists are still exploring.

2. Affects Caregiving

Providing care for an older loved one can often cause the caregiver stress and even health issues. In a review of 24 studies about caregivers – particularly those caring for dementia patients – they found higher levels of cortisol, poor sleep and psychological burden. On the other hand, when the same caregivers did leisure activities and cognitive-behavioral therapy, it helped to level cortisol spikes.

On the receiving end of the spectrum, caregiving can reduce cortisol levels. In an extremely specific study being released in Turkey in June, anesthesiologists studied the difference in cortisol levels in kids who were receiving tonsil or adenoid surgery. For those whose moms were allowed to stay in the room until the kids were put to sleep, they felt comforted and had lower cortisol levels. They also had lower cortisol levels when mom joined them in the recovery room, too. The cool effect? Moms also had lower cortisol levels when they were able to stay with their kids longer before surgery and join them in the recovery room soon after surgery.

3. Social Intolerance Makes It Worse

Discrimination has been associated with elevated cortisol levels in many studies in recent years, measurable through saliva, blood and urine. In the U.S., several studies have focused on the heightened cortisol levels in African Americans, suggesting links to the increased risks for heart disease, high blood pressure and hypertension. A University of Massachusetts study coming out later this month investigates the association between lifetime discrimination and chronic stress cortisol measured in the hair. As expected, discrimination highly predicted cortisol levels in young adults from diverse backgrounds. If we know that now, how can we help groups reduce stress (or really, discrimination) to fend off the potential of chronic disease later?

4. Cortisol Could Differ in Men and Women

Many studies that use the Trier Social Stress Test (a gold standard in stress testing) have found a difference between the sexes in salivary cortisol. In April, a research team in Canada looked at 34 different studies that used the stress test and found a significant difference between the sexes, with men having higher cortisol numbers at peak and recovery periods. They suggest the differences can be attributed to the different methods used across the studies. Future research will tell us whether we need to adjust the famous stress test as we know it — or begin to observe men and women differently during stress studies.

5. Our Habits Impact Cortisol

It makes sense that psychological stress can impact physiological stress. What we encounter in our daily lives in our minds affects what happens to our bodies. To extend that, our ongoing habits change how true that transfer effect is. In a study published in Singapore in April, researchers found that men with poor sleep habits were more stressed and had higher cortisol levels after an “all-nighter” that required them to get little sleep for one night. Those with regular sleep habits, however, saw less of an impact on their stress and cortisol levels. Similarly, studies have shown that regular exercise can reduce the roller coaster spikes and drops in cortisol that is associated with stress. As we learn more about the hormone, we can better care for ourselves and moderate its harmful effects on our bodies.

Image: Eder Zavala of University of Exeter, CC-BY

Carolyn Crist is a freelance health and science journalist for regional and national publications. She writes the Escape Artist column for Paste Travel, On the Mind column for Paste Science and Stress Test column for Paste Health.

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