Learning about Genetics and Your Physical Fitness

At one time, about 25 years ago, I was quite concerned about my physical fitness. I was running at least 3 miles every other day, and even doing some body-building routines. If I had had available the following blog posting, “How Much Does Genetics Really Affect Your Fitness?” I would have been all over it. Today, I am not so much interested in physical fitness per se.

But I was attracted to the article from the standpoint of genetics, however, especially since I have been working with DNA tests.

So who provided this blog posting? It was written by Beth Skwarecki, for the Fitness category of the blog, LifeHacker. According to an entry on Wikipedia (https://en.wikipedia.org/wiki/Lifehacker):

Lifehacker is a weblog about life hacks and software which launched on January 31, 2005. The site is owned by Gawker Media. The blog posts cover a wide range of topics including: Microsoft Windows, Mac,Linux programs, iOS and Android, as well as general life tips and tricks. The staff updates the site about 18 times each weekday, with reduced updates on weekends. The Lifehacker motto is “Tips and downloads for getting things done.”

The central idea of the posting is that there are a lot of things that enter into your conditionng along with genetics: “your diet, your exercise schedule, and the types of workouts you do, to name a few. But genetics is also a big factor.”

Skwarecki writes “There are genes for aerobic fitness and for muscular power, for adaptability to training, and for the size and shape of your body. To understand how your DNA affects your fitness, we talked to someone who has extensively studied this exact question: Stephen Roth, a professor in the Department of Kinesiology at the University of Maryland. The gist is this: We each draw something different in the genetic lottery, but we can always improve on what we’ve got.”

Here are some ballpark figures on heritability of athletic traits. The higher the heritability, the more you can blame genes, rather than training, for the difference between a couch potato and a star athlete.

●Aerobic fitness: about 40-50% heritable
●Strength and muscle mass: about 50-60% heritable
●Your mix of “slow twitch” and “fast twitch” muscle fibers (basically, whether your muscles are better at endurance or sprinting): about 45% heritable
●Height: about 80% heritable
●Competing in sports, at all: 66% heritable.
Trainability itself has a genetic factor, too. If you and your gym buddy follow the exact same program, starting at the exact same fitness level, one of you might end up stronger than the other.
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Here’s one more complicating, but hopeful factor: Athletic talent has many components. Maybe you can’t run as fast as one of your soccer teammates, but you have a better eye for where the ball is going to be and a more powerful kick once you’re there. Or maybe your cardio endurance isn’t great, but you have long legs and an efficient running stride. So don’t give up, even if you’re convinced you got a few dud genes.

Genetics is hard. Out of 20,000 human genes, Roth points out, only hundreds have been studied, and only dozens carefully studied, for their role in exercise. Just because we know a gene exists doesn’t mean we understand how it works, or what turns it on.

To read the LifeHacker blog posting, go to http://vitals.lifehacker.com/how-much-does-genetics-really-affect-your-fitness-1747333767

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