Being lazy could be in your genes, a new study reveals.
Research published in the American Journal of Physiology shows that certain genetic traits may predispose people to being more or less motivated to be active.
The study, led by Professor Frank Booth and his colleagues at Missouri University, selectively bred rats so some showed traits of being excessively active or extremely lazy.
Researchers measured how much each rat willingly went on a running wheel over six days.
They bred the top 26 runners with each other and bred the 26 laziest rats with one another. They repeated this process through ten generations and found that the family line of active rats chose to run ten times more than the line of lazy rats.
Once the researchers created their 'super runner' and 'couch potato' rats, they studied the levels of mitochondria in muscle cells, compared body composition and conducted thorough genetic evaluations of each rat.
Co-author Dr Michael Roberts said: "While we found minor differences in the body composition and muscle cells of the rats, the most important thing we identified were the genetic differences between the two family lines."
Experts say the study indicates that genetics could play a role in exercise motivation, even in humans.
"This could be an important step in identifying additional causes for obesity in humans, especially considering dramatic increases in childhood obesity," said Prof Booth.
"It would be very useful to know if a person is genetically predisposed to having a lack of motivation to exercise, because that could potentially make them more likely to grow obese."
Out of more than 17,000 different genes in one part of the brain, researchers identified 36 genes that may play a role in predisposition to physical activity motivation.
Now that the researchers have identified specific genes, they plan on continuing their research to explore the effects each gene has on motivation to exercise.
- DAILY MAIL