An article in the New York Times examined a National Institute of Mental Health study that now gives better insight as to why physical activity leads to happier, less anxious people. Although it is commonly known that exercise releases mood-boosting endorphins, many do not know why it occurs or the physical processes of the brain during a workout.
Researchers at the NIMH experimented on both aggressive and even-tempered male mice to find the answers. The dominant male mice got their own private cages, and when they were integrated with the others, they used several intimidation techniques against the defenseless mice. After two weeks of living with their aggressive neighbors, the skittish mice were severely nervous and stressed.
But another group of even-tempered mice were not as intimidated by the aggressive mice. This experimental group had been given an exercise wheel and an exploratory tube in their cage. Although the mice were submissive toward the more aggressive male rodents, they did not appear to be nervous.
Michael L. Lehmann, a postdoctoral fellow at the institute and leader of the study said, “In people, we know that repeated applications of stress can lead to anxiety disorders and depression. But one of the mysteries of mental illness is why some people respond pathologically and some seem to be stress-resistant.”
The scientists who conducted the study determined that the stress-free, exercising mice had neurons firing in the medial prefrontal cortex, which is an area of the brain that is for emotional processing in both animals and humans. Neurons had also been firing in some of the linked parts of the brain such as the amygdala, or the area of the brain that processes fear and anxiety, according to the article. The mice that did not have access to the wheel or the exploratory tube did not have this kind of brain activity.
Although the experimenters know that the mice are not people, they believe that what the rodents experienced is well represented in human relationships. For example, bullying and teasing are a constant source of stress in humans’ lives, just as it was present in the mice cages.
An encouraging finding in the mouse experiment was that the mice only ran when they pleased and received all the mental health benefits. “Exercise can help us feel strong and empowered because we’re doing something for ourselves,” Brooke Randolph, an Indiana Licensed Mental Health Counselor, said.
“Exercise can also improve mood because it allows us to recover mentally while we engage physically,” she said.
Exercising has many obvious physical benefits, but it is important to remember how it affects the psyche, anxiety, and mental health of a person.