Swimming gives your brain a boost – but scientists don’t yet know why it’s better than other aerobic activities

Studies in humans have found a strong relationship between concentrations of brain-derived neurotrophic factor circulating in the brain and an increase in the size of the hippocampus, the region of the brain responsible for learning and memory. Increased levels of brain-derived neurotrophic factor have also been shown to improve cognitive performance and help reduce anxiety and depression. In contrast, researchers observed mood disturbances in patients with lower concentrations of brain-derived neurotrophic factor.

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Aerobic exercise also promotes the release of specific chemical messengers called neurotransmitters. One of them is serotonin, which when present in increased levels is known to reduce depression and anxiety and improve mood.

In studies on fish, scientists have observed changes in genes responsible for increasing levels of brain-derived neurotrophic factors as well as increased development of dendritic spines – protrusions on dendrites or elongated portions of cells. nervous – after eight weeks of exercise compared to controls. . This complements studies in mammals where brain-derived neurotrophic factor is known to increase neuronal spine density. These changes have been shown to help improve memory, mood, and cognition in mammals. The greater density of the spine helps neurons make new connections and send more signals to other nerve cells. With repetition of signals, connections can become stronger.

But what is special about swimming?

Researchers don’t yet know what the secret swimming sauce might be. But they are getting closer to understanding.

Swimming has long been recognized for its cardiovascular benefits. Because swimming involves all of the major muscle groups, the heart has to work hard, which increases blood flow throughout the body. This leads to the creation of new blood vessels, a process called angiogenesis. The increased blood flow can also lead to a significant release of endorphins, hormones that act as a natural pain reliever throughout the body. This surge causes the feeling of euphoria that often follows exercise.

Most of the research to understand how swimming affects the brain has been done on rats. Rats are a good laboratory model because of their genetic and anatomical similarity to humans.

In a study in rats, swimming was shown to stimulate brain pathways that suppress inflammation in the hippocampus and inhibit apoptosis, or cell death. The study also showed that swimming can help support neural survival and reduce the cognitive impacts of aging. While researchers don’t yet have a way to visualize apoptosis and neuronal survival in people, they are seeing similar cognitive results.

One of the most attractive questions is how, in particular, swimming improves short and long term memory. To determine how long the beneficial effects can last, the researchers trained rats to swim 60 minutes a day for five days a week. The team then tested the rats’ memory by having them swim in a radial-arm aquatic maze containing six arms, including one with a hidden platform.

The rats had six attempts to swim freely and find the hidden platform. After just seven days of swimming training, the researchers found improvements in both short and long-term memory, based on a reduction in the mistakes the rats made each day. The researchers suggested that this improvement in cognitive function could provide a basis for using swimming as a means of repairing the damage to learning and memory caused by neuropsychiatric diseases in humans.

Although the jump from studies in rats to humans is substantial, research in humans produces similar results that suggest a clear cognitive benefit of swimming at all ages. For example, in a study examining the impact of swimming on mental acuity in older adults, researchers found that swimmers improved their mental speed and attention compared to non-swimmers. However, this study is limited in its research design, as the participants were not randomized and therefore those who were swimmers before the study may have had an unfair advantage.

Another study compared cognition between land athletes and swimmers in the young adult age range. While the water immersion itself didn’t make a difference, the researchers found that 20 minutes of moderate-intensity breaststroke improved cognitive function in both groups.

Children also enjoy swimming

The brain benefits of swimming also appear to stimulate learning in children.

Another research group recently looked at the link between physical activity and the way children learn new vocabulary words. The researchers taught children aged 6 to 12 the names of unknown objects. Next, they tested their accuracy at recognizing these words after performing three activities: coloring (resting activity), swimming (aerobic activity), and a CrossFit-type exercise (anaerobic activity) for three minutes.

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They found that children’s accuracy was much higher for words learned after swimming compared to coloring and CrossFit, resulting in the same level of recall. This shows a clear cognitive advantage of swimming over anaerobic exercise, although the study did not compare swimming with other aerobic exercise. These results imply that swimming even for short periods is very beneficial for young developing brains.

The details of the time or laps needed, the swimming style and the adaptations and cognitive pathways activated by swimming are still being worked out. But neuroscientists are getting closer and closer to gathering all the clues.

For centuries people have been looking for a fountain of youth. Swimming might just be the closest we can get.

This article is republished from The Conversation, a nonprofit news site dedicated to sharing ideas from academic experts. It was written by: Seena Mathew, Mary Hardin-Baylor University.

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Seena Mathew does not work, consult, own stock or receive funding from any company or organization that would benefit from this article, and has not disclosed any relevant affiliation beyond her academic position.