Many studies have shown a relationship between higher levels of aerobic fitness and healthy cognitive functioning. New research suggests that a mechanism underlying this association may involve increases in gray-matter volume and total brain volume as well as specific increases in both gray and white matter in certain parts of the brain.

Researchers at the German Center for Neurodegenerative Disease, University of Greifswald, found that evidence of high levels of cardiorespiratory fitness, based on three measures—ventilatory threshold, VO2max and maximal work capacity—were consistent with findings of increased brain volume. In particular,  brain areas that play a role in stress regulation and memory—like the hippocampus and parts of the prefrontal cortex—have more gray matter in people with demonstrably high levels of aerobic fitness.

Findings are based on data review from 2,103 adults ages 21–84. Study authors concluded that “higher cardiorespiratory fitness is associated with larger brain volumes in several brain regions that are not primarily connected to motor-related functions. Older people seem to have a stronger benefit in the memory-sensitive hippocampal region . . . .” Researchers, however, cannot rule out that people with greater brain volumes may have higher cardiorespiratory fitness. In other words, cause and effect is not yet proven. More research is recommended.

Read the full study in Mayo Clinic Proceedings (2020; 95 [1], 44–56).