Taking a brisk walk or bike ride may stave off cognitive decline better than reaching for the daily crossword puzzle, says a new study published in the journal Neurology. Researchers at Scotland’s University of Edinburgh reviewed the medical records of more than 600 Scots born in 1936 that were given MRI scans at age 73.

“People in their 70s that participated in more physical exercise, including walking several times a week, had less brain shrinkage and other signs of aging in the brain than those that were less physically active,” says study author Alan J. Gow, Ph.D.

Surprisingly, the study showed that participating in mentally and socially stimulating activities, such as visiting family and friends, reading or even learning a new language, did little to ward off the symptoms of an aging brain. Study participants will undergo a second MRI scan at age 76, and researchers plan to compare the two scans to see if the links between exercise and better brain health hold up.