High-intensity exercise reduces cortisol production during stressful tasks by 25%, suggesting vigorous activity can preemptively dampen the body's stress-response system. Digest
Stress can either sharpen performance or slowly wear down the body, depending on how frequently and intensely it strikes. Chronic stress, especially the kind triggered by psychological or social pressures, can lead to depression, anxiety, and other serious health problems. A recent study found that vigorous exercise reduced cortisol—the body's primary stress hormone—by about 25% in response to an intense social stress task, compared to lower-intensity exercise.
In this experiment, researchers randomly assigned 83 healthy young men to walk or run on a treadmill for 30 minutes at one of three different intensities: light (30% of heart rate reserve), moderate (50%), or vigorous (70%). After a 45-minute break, participants completed a well-established lab stressor known as the Trier Social Stress Test. Researchers collected saliva samples before, during, and after both the exercise session and the stress task to measure changes in cortisol levels over time.
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The men who exercised at the highest intensity had significantly lower cortisol levels during the stress task than those who exercised at light or moderate intensities. Their stress responses were not only smaller, but they also returned to baseline more quickly. The researchers also found that the amount of cortisol released during exercise was linked to the reduction in cortisol production during the later stress task—those with bigger exercise-related spikes had smaller stress-related spikes.
These findings suggest that one vigorous workout can help "pre-activate" the body's stress-response system in a way that makes it less reactive later, acting as a hormetic stressor. Learn more in this clip featuring Dr. Rhonda Patrick.