Genes, Jeans, and Long Distance Runners
I was recently sent an article discussing how exercise can positively influence brain power. Something from the article that stuck with me was the mention of some people’s genetic predisposition for exercise motivation.
We tend to gloss over how genes affect our bodies and habits even though they can have more impact than you think. So, I’m using this opportunity to take you on a deep dive into genes, body types, and exercise motivation. Let’s get to it!
Genes, Explained
No, I’m not talking about your Levi’s (pause for laughter…)
Genes and genetics are terms commonly used when discussing body types and health, but there’s not a lot of discussion on what these things mean. Many of us learned in 9th-grade science, but here’s a little refresher if you’ve forgotten!
The word gene is a little tricky to define, but the function of a gene is not! According to the NIH, “The gene is considered the most basic unit of inheritance.” Genes code proteins, the building blocks of the human body, using information that determines some physical and biological characteristics.
Genes are passed from parents to offspring, meaning that the way our proteins come together is, in part, predetermined by our parents and their genetics.
Genetics and Body Types
An ongoing problem I’ve discussed is that a person’s weight/body shape/size is often exclusively blamed on their actions and behaviors. While there is some personal responsibility we need to take for our health, it’s nowhere near that simple.
It’s easy to make the argument “calories in, calories out,” but Harvard Health discusses the way genetics and environment also influence weight and body type.
Harvard Health’s article explains that over 400 genes have been identified as having a part in the causes of overweight or obesity, though only a few seem to play significant roles.
Genes can contribute to weight by affecting:
Satiety (or how full you feel)
Appetite
Food cravings
Metabolism
The tendency to eat as a coping mechanism
Body-fat distribution
What makes this even trickier is how specific it is to each individual. According to this article, “for some people, genes account for just 25% of the predisposition to be overweight, while for others the genetic influence is as high as 70% to 80%.”
Those with higher genetic influence might struggle to lose weight and keep it off, due to no fault of their own. Yet these factors are rarely accounted for in regular life, where gaining weight, having difficulty losing weight, and having larger body size in general are seen as personal failures.
The Predisposition for Physical Activity
The influence of genes on physical activity isn’t as widely discussed as genes and body type. However, this article on genetics and exercise states “There is evidence…that DNA sequence differences contribute to human variation in physical activity level, cardiorespiratory fitness in the untrained state, cardiovascular and metabolic response to acute exercise, and responsiveness to regular exercise.”
Multiple studies are drawn from to provide a comprehensive review of what has been discovered in recent years thanks to advances in technology and research methods.
ACTN3
This article on genetics and athletic performance dives into some of the ways genetics affect the composition of our bodies, and therefore our predisposition for physical activity and athletic performance.
The article details one of the best-studied genes in athletic performance research. This gene, ACTN3, contains the information for making a protein mostly found in fast-twitch muscle fibers. Fast-twitch muscle fibers contract quickly but also tire quickly. These fibers are ideal for quick bursts of power or strength, like sprinting, and this gene is seen commonly in athletes like short-distance runners.
A variant of ACTN3 leads to abnormally short protein which breaks down quickly. This variant, when found in both copies of the gene, can mean this fast-twitch blueprint is entirely absent, leading to more slow-twitch muscle fibers. Slow-twitch muscle fibers contract slowly and tire slowly, making them ideal for endurance activities, like cycling. Some studies show this variant of the gene is common in endurance athletes, like long-distance runners.
Similar to how the influence of genes on weight varies, the article cites a study that found genetic factors make up 30-80% of individual differences in athletic performance traits.
Both of the above articles identify other ways genes are associated with physical activity. They can affect:
The production of energy for cells, including how carbohydrates are metabolized
The function of skeletal muscles, including muscle power and strength
Communication between nerve cells
Each of these predetermined factors come together to create a very unique approach to physical activity capabilities and levels for every individual.
The Implications
Ongoing research continues to support the correlation between genetics and body type, as well as genetics and exercise motivation. However, it’s important to note that this makes no difference in how important exercise and proper nutrition are to every individual. Regardless of how we’re wired, exercise is important for a long, pain-free, mobile life!
These findings are not an excuse to be inactive or to throw your health by the wayside. They are validation for those who have to work harder, often to see fewer or slower results.
This research also supports the need for education on body diversity and the dismantling of fatphobic ideas and behaviors. An especially important line in the conclusion of this article on exercise genomics and genetics calls for the recognition of human individuality and an understanding of the influence of different DNA sequences in public health policies. I would claim this call has generally been ignored.
Approaching health as a one-size-fits-all concept and assigning labels like “unhealthy” and “lazy” to those who don’t fit the norm has created an environment that is dangerous and deadly. Allowing space for new research and adapting policies and practices to fit individuals is the only way real change can be made.
The Takeaway
I think there’s a bit of freedom in this information. You don’t have to force yourself to love the same activities that other people in your life love because that’s just not how you’re wired. Explore other forms of movement and exercise until you find some options that work for you.
It might never be easy, but it will get easier. You might never fall in love with these activities, but you’ll come to appreciate what they do for your body and how they make you feel.
Again, the point of this information isn’t to offer an excuse to stay sedentary or give up quickly. But, just as some of the above articles mentioned, recognizing that human individuality runs as deeply as our very foundation is essential to build inclusive and effective public health policies and environments.
As always, if you have any questions about this topic or want to discuss the articles I’ve cited above, I would love to chat!
Please consider sharing this content with friends and family to help open the door for these conversations and discoveries.
Photo by Gary Butterfield on Unsplash