Do high-intensity workouts raise cortisol? Here's why the stress hormone isn't always bad

In recent years, wellness influencers have become fixated on cortisol, blaming the stress hormone for various symptoms, including a puffy face and excess belly fat. Many suggest that high-intensity or prolonged aerobic exercise puts too much stress on your body and causes your cortisol level to spike in an unhealthy way.

But scientists say this is a misunderstanding of cortisol’s role in the body. A surge in cortisol, they add, is not always bad, especially in response to exercise. We asked experts to explain the science around exercise and cortisol.

CORTISOL IS ESSENTIAL TO GOOD HEALTH

Cortisol’s main role is to help your body respond to stress: When you are under strain, your adrenal glands release the hormone to help set off the so-called fight-or-flight response. Cortisol helps increase blood flow to your muscles and gives you a burst of energy by spurring your body to convert fast-acting carbohydrates to fuel.

These responses would be essential if, say, you were being chased and needed to run away, said Dr Lena Fan, an endocrinologist and assistant professor at the Icahn School of Medicine at Mount Sinai. Cortisol also helps you fight off infection and inflammation, and helps regulate heart rate, blood pressure, blood sugar and sleep cycle.

CORTISOL DISORDERS ARE UNCOMMON

While chronically high cortisol may seem common from conversations on social media, cortisol disorders are, in fact, rare, Dr Fan said. Only about 1 per cent of the population has cortisol levels above the normal range. Even if you have chronic stress or anxiety, your cortisol levels are likely to increase but stay within the normal range, she said.

STRENUOUS EXERCISE CAN LOWER CORTISOL OVER TIME

The stress of exercise signals to your body that it should release cortisol. The more you exert yourself, the more cortisol is released. Anthony Hackney, a professor emeritus of exercise physiology at the University of North Carolina, said this is a good thing during a workout because the hormone helps deliver more oxygen to your muscles. Cortisol typically stays high for a few hours after exercise, but once you’ve recovered and refueled, it drops back down, often to a lower level than where it started.

PROPER FUELING AND RECOVERY ARE KEY

In order for strenuous exercise to lower stress and your baseline cortisol level, you have to eat enough and build in time for recovery, said Dr Marie Schaefer, a co-director of the women’s integrated sport, exercise and research centre at the Cleveland Clinic.

If you do a hard workout but haven’t eaten enough fuel, including carbohydrates, it may feel more challenging and your cortisol will likely remain high for longer afterward, Dr Schaefer said. Overtraining, or doing long, hard workouts without proper rest and recovery, can negate some of the stress-lowering benefits of exercise.

By Danielle Friedman © The New York Times Company

The article originally appeared in The New York Times.

Source: New York Times/mm