Regular exercise may be the easiest way to get smarter and a lot of people sure could use it. From Ross Pomeroy at realclearscience.com:
Physical activity can do wonders for the body. Exercise can trim weight, chisel muscles, and strengthen the lower back, among many other benefits. Less overt, but no less consequential, physical activity can also buff up your brain. Science is increasingly revealing that the brains of those who regularly work out can look very different compared to the brains of people who don’t.
Changes can start to occur in adolescence. Reviewing the scientific literature in 2018, researchers from the University of Southern California found that for teens aged 15-18, regular exercisers tended to have larger hippocampal volumes as well as larger rostral middle frontal volumes compared to healthy matched control teenagers. The hippocampus is most commonly associated with memory and spatial navigation, while the rostral middle frontal gyrus has been linked to emotion regulation and working memory. Studies suggest that these structural changes translate to improved cognitive performance and better academic outcomes.
Exercise’s brain augmenting qualities extend into adulthood, even though the brain tends to be less ‘plastic’ (easily changed) as we get older. Rutgers University scientists beautifully demonstrated this in a study published early last year:
The researchers recruited older African Americans, all previously sedentary, to complete twenty weeks of twice-weekly cardio-dance exercise classes held at local churches and senior centers. As compared to the control group comprised of community members of similar age and background who did not exercise, those in the program showed significant improvements in dynamic brain connectivity (or “neural flexibility”) in their hippocampus and surrounding medial temporal lobe, as measured using resting-state functional MRI.
In another study, published in August 2019, scientists looked at 45 sets of adult identical twins, who, within their pair, all differed greatly in physical activity levels. “More active co-twins showed larger gray matter volumes in striatal, prefrontal, and hippocampal regions, and smaller gray matter volumes in the anterior cingulate area than less active co-twins,” the researchers found.