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March 13, 2014 Volume 35, No. 23

Exercise motivation might be in the genes, scientist says

Alternate text

Frank Booth

Frank Booth talked of dangers of inactivity at Saturday lecture

Studies showing that most Americans are inactive — engaging in less than an hour’s worth of moderate exercise a week  — are so commonplace that they have lost their shock value. Unlike cigarette smoking, for which there are strong anti-smoking campaigns, being inactive carries with it little stigma. Couch potatoes even engage in some witty gallows humor about their lifestyle.

But Frank Booth isn’t laughing. 

Booth, an MU professor of biomedical sciences, claims that inactivity can be lethal. Just as smoking is linked to more than 400,000 deaths in the United States each year, inactivity places tens of millions of Americans at risk for major chronic ailments (coronary heart disease, various cancers, Type 2 diabetes, hypertension, obesity) and early death. 

“Relative risk of death correlates to how active you are during life,” Booth said at his March 8 lecture on genetics and exercise in Monsanto Auditorium, part of MU’s Saturday Morning Science lecture series. “There is one U.S. death every 43 seconds due to lack of exercise,” he said.

But telling people to exercise hasn’t done much for people’s motivation, despite researchers’ documenting the health consequences, Booth said. 

Perhaps science can offer another approach.

Booth’s lecture focused on why some people seem more motivated to exercise than others. Researchers have attributed the reasons to culture, geography, psychology, hormones and — the point of Booth’s lecture — genes. Booth is leading research to develop a way to tweak certain genes in sedentary people to overexpress exercise motivation.

But this assumes that genes have something to do with motivating people to spend their leisure hours on a couch or a treadmill. Since 2009, Booth has examined this question in his research. He and colleagues have interbred two sets of lab rats — one group to become couch potatoes and the other exercise fanatics. Then, through MU’s DNA Core Facility, they examine gene differences between the groups.

Through selective breeding of nine generations, Booth created indolent rats motivated to run on the wheel for 10 minutes a day, and Olympian rats who ran six to eight hours. “There was a 10-fold difference of animals wanting to run on their own,” he said. 

He and colleagues discovered that exercise motivation appeared to have a genetic component. In the Olympian rodents, researchers isolated genes high in dopamine, the pleasure molecule. These animals apparently got a rush from exercise. The couch-potato rodents did not, findings suggest.

Booth hopes to help develop a non-addictive drug that stimulates genes in inactive people to get them to exercise.

Even so, when talking about genes expression, qualifiers are needed. Genes are not fate. Many factors contribute to the biology and behavior that makes someone fit or fat.

Booth cited studies and cutting-edge, if baroque, health measurements suggesting that fit people who feel 10 or 15 years younger than their numerical age are exactly right, at least when it comes to bodily health. Studies also indicate that a fit body many times correlates to a fit mind. 

Booth, who is fit and agile in his 70s, recommends that people do strength training at least two to three times a week and aerobic workouts four times a week.

To read a MIZZOU magazine feature on Frank Booth and the biology of exercise, click here.