Lazy? Blame Your Genes

Link between mental growth, physical motivation

Apr 16, 2014
Outside Magazine
If you're lazy by nature, you'll have to outrun your genes.

If you're lazy by nature, you'll have to outrun your genes.    Dirima/Thinkstock

Next time you can't gather the willpower to lace up your running shoes and go for a jog, blame your genes. Researchers at the University of Missouri have identified a possible link between the genes that motivate people to exercise and the speed of mental maturation.

In other words, the genes responsible for getting you moving appear to be tied to the ones that help your neural pathways develop, making the study the latest to suggest that the benefits of exercise extend far beyond the physical.

Frank Booth, a professor at MU's veterinary school, selectively bred rats that exhibited either extreme activity or extreme laziness, solidifying these traits during 10 generations of reproduction. The rats in the active lineage proved 10 times more likely than the "lazy" rats to decide on their own volition to run on an exercise wheel.

"We found a big difference between the amount of molecules present in the brains of active rats compared to the brains of lazy rats," Booth said. "This suggests that the active rats were experiencing faster development of neural pathways than the lazy rats."

These findings suggest that when kids exercise, they could be developing their neural pathways on top of getting fit and having fun. The neural pathways kids create by exercising could, in turn, set a precedent for a lifetime of motivation to stay physically active.

"This could show the benefits of exercise for mental development in humans, especially young children with constantly growing brains," Booth said.

Prior to this study, MU scientists had already proven the existence of a genetic predisposition for exercise motivation, but the new findings are the first to link such tendencies to mental development.

If you're a habitual couch potato, this news probably won't help you change your ways, but at least now you understand why getting out the door sometimes can be such a struggle.