Laziness may correlate with our genes.
When it comes to our physical activity, are we limited due to our genetics?
This year’s honoree Pease Family Scholar, Dr. J. Timothy Lightfoot answered this question with his lecture, “Can You Be Born a Couch Potato? The Genetics of Physical Activity”, Thursday evening in the Great Hall of the Memorial Union.
The Pease Family Scholar program was created by Dean Pease and his wife Sally, in memory of his parents Harvey and Bomell Pease. Pease chaired the department of health and human performance from 1987 to 1990. The Pease Scholar program allows Iowa State to bring a leading scholar in kinesiology each year.
Lightfoot is the director for the Sydney and J.L. Huffines Institute for Sports Medicine and Human Performance, and currently the Omar Smith Endowed Professor of Kinesiology at Texas A&M University.
Lightfoot’s federally funded research focuses on the genetics of daily physical activity. What started the research was the curiosity of why people weren’t active if they knew the benefits, and was it due to our genetic traits.
“Moderate physical activity is linked to a whole host of positive health outcomes, but Americans aren’t very active,” Lightfoot said. “If we get people active, it may reduce the problems we have in healthcare.”
The models he used for this research were human and mice studies. The mice studies were due to the similarities with humans in cardiovascular responses.
“If you put a human on a treadmill and tell them to exercise as much as you want or as fast as you want, humans will self-select 70 percent of their max capacity,” Lightfoot said. “Mice do the same thing.”
Based on 43 studies that involved 331,334 human subjects and 1,861 rodent subjects, it resulted that physical activity is caused by 50-60 percent genetics and 40-50 percent unique environment. The unique environment pertains to the things that happen to you as an individual.
The answer to the question “can you be born a couch potato?”, is yes.
The exact regulating mechanisms are unknown. There is tentative evidence that suggests the brain and muscle mechanisms regulate physical activity. Through neurotransmitters controlling reward behavior, and contractile and metabolic proteins in skeletal muscle. There may also be biological factors, like sex hormones, that are involved.
Another thing to consider are implications for decreasing activity through direct environmental interference, from food and environmental toxicants. One toxicant mentioned was phthalates.
“Phthalates are common in the environment,” Lightfoot said. “They are in flooring, construction materials, more importantly they are in most personal care products.”
One study tested pregnant mice given doses of BBP (benzyl butyl phthalate). After the animals were born, results concluded that the mice given BBP had a decreased activity level than the ones who did not receive any BBP.
Even though research and studies have determined that there is a significant genetic control that regulates activity and there are implications from our environment, Lightfoot has a take home message for all of us.
“Activity level is a predisposition and not a predestination. So, don’t let your genes stop you from being active,” Lightfoot said.