The case for cardio exercise just keeps on getting stronger. First a University of Princeton team shows that exercise lets lab rats (Note: I mean actual laboratory rats here) produce neurons with improved stress response (i.e. they don't respond), and now a group of Swedish neuroscientists is telling us that improved cardiovascular fitness actually makes young men smarter:
The study looks at more than 230.000 adolescent men at their time of enlistment into the Swedish army, and finds a very strong effect of cardiovascular fitness on multiple dimensions of intelligence. Newly recruits who performed best on a regular ergonomic cycle also performed strongest on a series of tests for global intelligence, verbal, visuospatial, logical and technical intelligence. As an even stronger test for this correlation, the researchers additionally assessed their subject's physical education records at age 15 and then mapped changes in fitness to changes in intelligence. They found that - on average - those young men who moved in their percentile ranking for cardiovascular fitness also moved in their percentile ranking for intelligence. In other words: Changes in intelligence from age 15 to age 18 seem to track changes in fitness.
A likely biological mechanism behind the observed effect relates to the impact of physical exercise on the brains plasticity (the brain's ability to adapt new situations and environments), and one of the physiological mediators for this mechanism may be the simple fact of improved blood circulation among those who exercise more. This relationship between exercise and improved cognitive function has of course repeatedly been shown for mice (basically cute pocket sized humans), but - as far as adolescent men - were concerned the scientific evidence has until now been somewhat inconclusive.
Although improved intelligence, and in consequence improved socioeconomic status and educational attainment later in life, show this very strongly relation to cardiovascular fitness, no such relation could be shown for muscle strength in this study; which again speaks for the mediating function of improved blood flow and circulatory consequences in causing the effect.
Aberg MA, Pedersen NL, Torén K, Svartengren M, Bäckstrand B, Johnsson T, Cooper-Kuhn CM, Aberg ND, Nilsson M, & Kuhn HG. (2009) Cardiovascular fitness is associated with cognition in young adulthood. Proceedings of the National Academy of Sciences of the United States of America. PMID: 19948959
<Cross-posted with Ingenious Monkey>