Born to Exercise: The Role of Genetics in Fitness

Melanie Rovinsky

Have you ever wondered why two people following the exact same fitness and diet regimen will often achieve different results? It turns out the answer may be genetics.

What do the scientists say?

The New York Times recently published an article on a new study that explored the genomes (hereditary information) of 473 healthy, white volunteers to examine the genetic influence on an individual’s receptiveness or resistance to exercise. The study’s participants underwent a five-month exercise program, after which some ended up more fit than others. The fitness level was measured by the increase of the amount of oxygen used in an individual’s body during exercise. While no demographical factors could explain the discrepancy, scientists did detect a significant difference in tiny segments of DNA called single-nucleotide polymorphisms, or SNPs. According to the results published by The New York Times, “exercisers who had 19 or more of these SNPs improved their cardiorespiratory fitness three times as much as those who had nine or fewer.”

What do SNPs have to do with my fitness?

SNPs are located on various genes and play a wide range of roles in your body’s functioning. One SNP detected during the study is responsible for how the body metabolizes fat. Dr. Claude Bouchard, the lead author of the study, claims that even if you do not possess the most desirable genes for exercise, you can still reap the benefits of getting off of the couch. While you may not increase your body’s consumption of oxygen, exercise can still help you improve your health, especially when it comes to lowering your blood pressure.

Do genetics dictate whether I love or hate exercise?

More and more scientists are saying yes. If you are bred from offspring that enjoy working out, there is a greater chance that you will also enjoy working up a sweat. Of course, enjoyment of exercise also depends on how a person feels during and after a workout. Studies on mice reveal that some people are, in fact, programmed to not want to be active. However, many scientists feel that these individuals can overcome their genetics with exercise. Working out releases dopamine in the brain, which causes your body to feel good. And if you work out regularly, your brain will develop a memory linking exercising to feeling good.