LOS ANGELES, Dec. 8 (UPI) -- Boys who are fit as teens grow up to be smarter men -- with higher IQs -- Swedish and U.S. researchers say.
The study, published in Proceedings of the National Academy of Sciences, correlates better cardiovascular scores for males as teenagers to greater education and income later in life.
The study sample of 1.2 million Swedish men born between 1950-1976 included 260,000 full-sibling pairs, 3,000 sets of twins and more than 1,400 sets of identical twins. The results for twins supported a link between cardiovascular health and intelligence rather than a reflection of genetic influences on cardiovascular health and intelligence.
"Direct causality cannot be established. However, the fact that we demonstrated associations between cognition and cardiovascular fitness but not muscle strength ... speak in favor of a cardiovascular effect on brain function," Nancy Pedersen of the University of Southern California in Los Angeles says in a statement.
Intelligence test scores increased as the aerobic fitness score at age 19 increased, the study said. However, the intelligence test scores did not go up similarly as muscle strength at age 19 increased. This supports the importance of getting healthier between the ages of 15-18 while the brain is still changing, the researchers say.
