Mens sana in corpore sano - a healthy mind in a healthy body - was one of the most popular sayings in traditional education. Researchers from the University of Gothenburg and the University of Southern California looked at the data for all 1.2 m Swedish men born between 1950 and 1976 who enlisted for mandatory military service at the age of 18. In every measure of cognitive functioning they analyzed - verbal ability, logical performance, geometric perception and mechanical skills - average test scores increased according to aerobic fitness. However, the link was only to aerobic fitness and not to muscular strength. Boys who got fitter between 15 and 18 showed significantly greater intelligence scores than those who became less healthy over the same time period and the boys who were fittest at 18 were more likely to go to college. Even among identical twins the twins who were fitter were more likely to perform better on intelligence tests.
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