Can Exercise Build Brain “Muscle”?

Exercise has repeatedly been found to be powerful medicine — so much so that several new studies explore whether it may even boost brainpower. The proteins amplified or created during activity may benefit learning, memory, and cognition and even help stave off Alzheimer’s disease and other forms of dementia.

“We’re seeing an increasing number of studies where proteins from outside the brain that are made when you exercise get into the brain and are helpful for improving brain health, or even improving cognition and disease,” Alzheimer’s researcher Rudolph Tanzi, PhD, a professor of neurology at Harvard Medical School and codirector of the McCance Center for Brain Health at Massachusetts General Hospital, tells the New York Times.

Most studies so far have focused on mice rather than humans, but the findings may eventually result in therapies and treatments.

In a study published in 2018 in Science, Tanzi’s team found that exercise provided cognitive benefit to mice engineered to have a version of Alzheimer’s. Activity elevated levels of brain-derived neurotrophic factor (BDNF), a key protein aiding neuroplasticity — the ability of the brain to change, grow, and rebuild itself.

Plus, Tanzi speculates that exercise at the earliest stage of ­Alzheimer’s development may provide “a potentially powerful disease-­modifying treatment strategy.”

For a study published in Nature in 2021, researchers injected blood from active mice into sedentary mice, who subsequently performed better on learning and memory tests. The exercise-enhanced plasma transferred clusterin proteins that may increase neuroplasticity and reduce the neuroinflammation connected with Alzheimer’s and other neurological disorders.

“Physical exercise is generally beneficial to all aspects of human and animal health, slowing cognitive aging and neurodegeneration,” the study authors write. They speculate that the benefits of exercise may someday be used to help patients with neurodegeneration and other forms of brain trauma.

A study published by the Alzheimer’s Association in 2022 is one of the most recent linking exercise and cognition in humans. Researchers found that physical activity promotes synaptogenesis, or the formation of synapses in the brain.

“Late-life physical activity (PA) is one of the most consistently recommended lifestyle modifications to support brain and cognitive aging,” the authors summarize. “PA is associated with a reduced incidence of Alzheimer’s-disease dementia, and inactivity alone is estimated to account for more than 4 million dementia cases.”