The various benefits of regular exercise on the human body are well-known. But fewer people realize that exercise benefits not just the body, but the mind as well. Indeed, recent studies have revealed that the connection between physical fitness and psychological health runs deeper than previously assumed, both in people with mental illnesses and in psychologically healthy people. Exercise not only improves brain performance in the short term, sharpening memory and information processing, but can also help maintain the health of the brain in the long term by lessening the impact of dementia in old age. While a lifelong routine of exercise is most likely to protect the brain against the worst effects of age-related psychological problems, exercise has also been shown to improve brain function immediately after as few as one workout. As such, when it comes to preserving and improving mental health, physical exercise plays a more substantial role than most of us likely assume.
Several studies were reported on in 2019 that represent substantial breakthroughs in medical understanding of the relationship between the brain and body. A study published in July, for instance, looked at the performance of semantic memory, or the portion of long-term memory involving ideas and concepts not related to personal experience, in older adults immediately following exercise. It found that after a single session of exercise, regions of the brain associated with semantic memory were more active, though this effect did not apply throughout the entire brain. While scientists used to believe that the human brain was fully formed and fixed by the time a person reaches adulthood, recent evidence has shown that the brain actually remains somewhat malleable throughout life. As semantic memory is often one of the first aspects of brain function to deteriorate with age, these findings give hope to people who are entering old age and are concerned about preserving their brain function through the end of their lives.
The results of this study are supported by other studies that examine how, at a molecular level, exercise changes the brain. Specifically, in a study published in January, scientists found that the hormone irisin may play a key role in preserving brain function, even in people experiencing age-related cognitive impairment. The study involved mice, but nevertheless provides insights about the function of the human brain, as all mammals are fairly genetically similar to one another. Irisin is a hormone that is released during exercise and helps the body metabolize energy while working out, improving the function of the body as well as the brain. It is thought to be involved in the development of Alzheimer’s disease, as the brains of people who did not have Alzheimer’s were found to contain irisin whereas the brains of people with Alzheimer’s had none. In the study, mice that were bred to develop dementia performed better on memory tests after being given a dose of irisin, and mice whose production of irisin was artificially blocked were prone to developing dementia.
Another study published in 2019 looked at how different forms of exercise affect the brain in different ways. While scientists have determined that aerobic exercise can improve memory and cognition by creating new neurons and reducing inflammation in the brain, less has been determined about the impact of weight training. As such, the researchers in this study developed a weight training program for rats, some of which had been given a substance that causes the development of dementia in animals, to determine whether weight training has the same positive effects on the brain that aerobic exercise does. The scientists found that the rats involved in the weight training program more successfully navigated a maze than those that weren’t, even for the rats with induced cognitive impairment. In fact, an examination of the rats’ brain tissue found that the rats who trained with weights were actually able to restore lost brain function, as their brains reshaped themselves to more closely resemble the brains of healthy rats. The results suggest that all forms of exercise, whether they focus on improving cardiovascular health or muscle mass, may support overall brain health.
While more work certainly has to be done to understand the full extent of the relationship between exercise and brain health, it is abundantly clear that frequent exercise is a key component of a healthy life. Anyone who is physically able to exercise is likely to benefit from a regular workout routine in any number of ways, some of which may not have even been discovered yet.