Study: Heritable link between cognitive and oxidative  function

Ryan lochte grill and gold medal

Ryan Lochte's (right) portrayal in the media epitomizes the dumb jock. However, two studies that came out last year found that heritable endurance running capacity and professional soccer player success are both positively correlated to cognitive function.

A study published last year in Physiology Behavior found that rats selectively bred for endurance running capacity had better cognitive function than rats selectively bred for poor endurance capacity (Selective Breeding for Endurance running capacity affects cognitive but not motor learning in rats, 2012.  Wikgren, et al.). The study bred the rats for 23 generations. With each generation, the rats were tested for endurance running capacity in five separate treadmill trials. The male and female rat with the highest endurance running test over the five trials were mated. Likewise, the male and female rat with the lowest endurance running test were bred. After 23 generations, high endurance bred rats and low endurance bred rats were tested for cognitive and motor function using a T-maze and Rotarod, respectively.

The high-endurance bred rats showed significantly higher ability on the T-maze when the strategy was shifted from a "shift-win" strategy to a "stay-win" strategy. A "stay-win" strategy means that prize food is placed in the same arm as the rat's first trial. When a "shift-win" strategy is employed, the prize food is placed in a different arm from the food in the initial trial. High-endurance bred mice's ability to perform better when the strategy is switched from "shift-win" to "stay-win" suggests either a greater propensity for cognitive learning and adaptability or a greater propensity for the "stay-win" strategy. There is no resin to believe that high endurance runners would be more inclined to the "stay-win" strategy. The ability to switch strategies is probably learned. Rats naturally employ the "shift-win" strategy when foraging for food because they would expect to find no food after eating all the food at a given location.  

Number of correct choices (+/− SEM) as a function of T-maze training. There were no significant differences between the groups in the T-maze test in acquiring the shift-win rule (left pane): both groups learned to a similar extent at a similar rate. However, when the rule was changed to the stay-win rule (right pane), the High Capacity Runner (HCR) rats performed significantly better, but were still unable to reach the chance level.

There was no significant difference in Rotarod performance. Rotarods measure balance, essentially motor learning. Therefore, from the study it can be concluded that high endurance runner bred rats have greater cognitive learning, but not motor learning.  

The authors speculate that the link between cognitive learning and endurance capacity may be oxidative metabolism. A higher level of, or more efficient, oxidative metabolism proteins in the muscles and brain would theoretically enhance cognitive capacity and endurance capacity, respectively. Whether this is the actual link remains to be seen.

Another study, found that successful soccer players had a greater proficiency in design fluency, a measure of cognition, creativity and response inhibition (not giving the same answer twice) than their novice counterparts. The study looked at Swedish soccer players across divisions  and genders (Executive Functions Predict the Success of Top-Soccer Players, 2012. Vestberg, et al.).  

The study found that not only did the professional soccer players have a greater design fluency than their non-professional counterparts, but that design fluency was correlated with success on the pitch, measured with the goals and assists recorded. The graph below shows that both men and women soccer (football) players at the top Swedish division (HD) had a significantly greater design fluency than soccer players in the lower Swedish soccer divisions (LD).

In Design Fluency (DF), a measure of cognition that includes creativity, multi-processing, response inhibition and cognitive flexibility, the High Division (HD) players had significantly better scores than the Low Division players (LD).  This difference was observed for both genders.  Note that High division and Low Division players have superior scores compared with the standard population (not shown).

The reason professional soccer players have a greater executive function is probably not tied to their endurance capacity. Setting up plays that result in goals and assists require strong executive function capacity.  

It is hard to draw any translational conclusions from either of these studies.  Humans, of course, do not have any programs breeding high capacity endurance runners. Because a high level of training is required to become a successful human endurance athlete, it is unlikely that we would see any correlation in humans between endurance capacity and cognitive function. However, both of these studies show that natural athletic ability should not be correlated with reduced cognitive function. These studies certainly seem to contradict the term "dumb jocks".

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