Class Make Up Blog 4/13 – Focus on Chapter 14

As the title of Chapter 14 suggests, “Sled Dogs Ultrarunner, and Couch Potato Genes”, David Epstein continued to explore the genetic influences on the worlds top athletes- and the role these genes play in the average person’s lifelong health journey. This chapter specifically looked at a person’s genetic predisposition to physical activity levels

Epstein starts off the chapter with the story of Lance Mackey. A dog sled racer and breeder, Mackey had great success because he bred dogs for the will to run rather than their speed.  WHile his hand was somewhat forced because he could not afford the expensive racing dogs, he looked for th dogs that simply wanted to run. Zorro, his pride an joy, was one of his first dogs and the beginning of his winning lineage.

Mackey used Zorro (above) to breed the first generations of racing dogs.

After Mackey’s crazy success, Heather Huson began to look extensively at the genetics of sled racing dogs.  In her 201 dissection of  breed composition and performance she showed Alaskan Huskies to be there own distinct breed and supported Mackey’s opinion that he won because his dogs wanted to run not because they were forced to.

While sled racing is exciting, what does winning a thousand-mile dog race mean for our athletes? Well, a lot apparently. It is easy to understand the role genetics play in athletic success in terms of body structure and muscle type, but it is not as blatant the role it plays is in drive and passion to train.  After discussing the genetics of huskies, Epstein turns to lab rodents bred to be runners.  They have also shown, that like the huskies, mice can be bred for work ethic.  In  Theodore Garland’s voluntary-runner breeding program he showed that while the bodies changes physically, the brain changed as well.  Mice who ran more than the average mice were bred together and resulted in “high-runner” mice who ran excessively. This genetic drive for physical activity can be seen in Pam Reed, an ultrarunner. She believes that running more than three hours a day may make some people ill, but not doing it would certainly make her ill. She has difficulty sitting still and is believed to be the human version of the mice bred to run. Taking the study a step farther, Garland dosed the mice with Ritalin and found that the levels of dopamine in the medicated mice matched the levels in the “high-runner” mice. Particular dopamine receptor genes have been linked to higher levels of physical activity, and can be further linked to attention deficit hyperactivity disorder (ADHD).  Ritalin, used on the mice in Garland’s study, is a common medication for those with ADHD to calm them and increase their focus.  Tim Lightfoot has studied the connection between ADHD, exercise and dopamine levels and believes that although Ritalin may be beneficial to keep students focused in class, it may be blunting their strong drive to be active.

I found the genetics of work ethic to be fascinating because you do not hear about it often. For example, during the NFL draft they tell you about players height, weight and other physical stats, but there is no category to quantify “drive” or “passion”.  The connection towards the end of the chapter to the treatment of ADHD also caught my attention. In 2008 when Michael Phelps had his incredible 8 gold medal run I was his biggest fan. I have read (maybe embarrassingly) read his autobiography multiple times. In No Limits, Phelps speaks to his experience with ADHD and his experiences with medications.  In this article in Psychology today, “From ADHD Kid to Olympic Gold Medalist” they explain how swimming became his medication by allowing him to release his nervous energy and increase his structure and focus.

While Phelps has the perfect body for a swimmer with freakishly large feet and hands and an abnormally long torso makes him a force to be reckoned with, his brain may also be home to perfect genetics we do not understand yet. I believe this chapter is eye opening and important because as a society we continue to over-medicate children with ADHD. These children may not all be olympians but these studies show that they may just need a physical outlet rather than Rtalin.