Boys interested in improving report card scores may want to take up running or bicycling. A study of 1.2 million men born between 1950 and 1976 determined a link between cardiovascular fitness and “intelligence.” Researchers from the Institute of Medicine at the University of Gothenburg, in Sweden, analyzed the physical capacity, brain power and socioeconomic status of men when they reported for military duty at age 18. The data, published in the December 8 issue of Proceedings of the National Academy of Sciences (2009; 106 [49], 20906–911) suggests that those men with greater cardiovascular fitness were more likely to be more intelligent and experience greater success.

Interestingly, there was no association between muscular fitness and the intelligence markers. “Male subjects with improved predicted cardiovascular fitness between 15 and 18 years of age exhibited significantly greater intelligence scores than subjects with decreased cardiovascular fitness,” stated lead study author H. Georg Kuhn. The authors could not say whether higher intelligence scores are a result of increased physical capacity. “We cannot assume that fitness per se increases cognitive function, so joining a gym does not by itself make you ‘smarter,’” added Kuhn. “But in order for optimal cognitive function/development to take place, regular cardiovascular fitness is needed.”