By Dr. Seena Mathew, University of Mary Hardin-Baylor — The Conversation US — 27 July 2021
Regular swimming has been shown to improve memory, cognitive function, immune response and mood. Swimming may also help repair damage from stress and forge new neural connections in the brain. But scientists are still trying to unravel exactly how and why swimming, in particular, produces these brain-enhancing effects. One key mechanism is through increased levels of a protein called brain-derived neurotrophic factor (BDNF). The neural plasticity that this protein stimulates has been shown to boost cognitive function including learning and memory, sharpen cognitive performance, and reduce anxiety and depression. Aerobic exercise also promotes the release of neurotransmitters such as serotonin, which at increased levels reduces depression and anxiety and improves mood.
Most research to understand how swimming affects the brain has been done in rats. In one study, swimming was shown to stimulate brain pathways that suppress inflammation in the hippocampus and inhibit apoptosis (cell death), and to support neuron survival and reduce the cognitive impacts of aging. Rats trained to swim for 60 minutes daily for five days per week showed improvements in both short- and long-term memory after just seven days — suggesting swimming could potentially repair learning and memory damage caused by neuropsychiatric diseases in humans. In studies in humans, swimmers have shown improved mental speed and attention compared with non-swimmers in the elderly. Among young adults, 20 minutes of moderate-intensity breaststroke swimming improved cognitive function. In children aged 6–12, accuracy at recognising newly learned words was significantly higher following swimming compared with both coloring (resting activity) and CrossFit-like exercise (anaerobic activity), showing a unique benefit of aerobic swimming for developing brains. Scientists are still working out which style of swim, the duration required, and which cognitive adaptations and pathways are activated — but the evidence is building that swimming may be the closest thing we have to a fountain of youth.