You may have your new years resolutions sorted but following through with your most ambitious fitness goals could be down to genetics.

By Mike Huyhn


Posted on December 6, 2019

Talk about a rude awakening. As another new year rounds the bend there are no doubt plenty of people plotting their annual fitness goals which they will never actually fulfil. You hopeful tragics get an ‘A’ for effort.

Have you ever wondered though why it’s easier for the dedicated gym junkies to lift, run, bike and swim on a regular basis whilst others find it hard to get off the couch at all?

Researchers from the Baylor College of Medicine did and that’s why they conducted a study to find out why this distinction in motivational behaviour between the dedicated and the lazy existed. The results from the study found that it’s not really your fault if you can’t be bothered gyming – it’s all in your genes.

The research entitled ‘DNA methylation in AgRP neurons regulates voluntary exercise behaviour’ was published in Nature Communications. It highlights the epigenetic control of the expression of certain genes. These particular epigenetic mechanisms are explained to be more malleable than pure genetics alone, suggesting that there is still a way to “program” people into being more physically driven rather than just blaming genetics.

How they reached this conclusion was through the creation of an “epigenetic couch potato” mouse. In this test subject, the researchers analysed changes in the DNA methylation in neurons within the hypothalamus. Basically science jargon which says they found a link between the couch potato mouse and voluntary exercise behaviour.

“Our earlier findings suggested that establishment of one’s physical activity ‘set point’ can be affected by early environment, and that this may involve epigenetics,” explained corresponding author Robert A. Waterland, PhD, professor of pediatrics nutrition at the USDA/ARS Children’s Nutrition Research Center at Baylor and Texas Children’s Hospital.

Further investigations were conducted to test whether DNA methylation in the brain affects energy balance. Researchers implemented running cages in the animals’ cages for eight weeks and observed the difference between two specific groups. The normal male mice ran approximately 6km every night whilst the mice with a specific gene blocked only ran half the distance. Naturally the latter group also lost less fat.

What the researchers concluded from the experiment was that the gene-deficient mice were capable of running the same distance as normal mice but simply lacked the desire to.

“Our findings suggest that epigenetic mechanisms, such as DNA methylation, that are established in the brain during fetal or early postnatal life, play a major role in determining individual propensity for exercise,” Waterland said.

“Nowadays, as decreases in physical activity contribute to the worldwide obesity epidemic, it is increasingly important to understand how all of this works.”