Your Exercise Capacity is Largely Inherited
Voluntary activity, such as daily exercise, is a highly heritable trait that can be passed down genetically to successive generations, according to biologists at the University of California, Riverside.
While working on mice in the lab, they found that activity level can be enhanced with 'selective breeding' – the process of breeding plants and animals for particular genetic traits.
Their experiments showed that mice that were bred to be high runners produced high-running offspring, indicating that the offspring had inherited the trait for activity.
"Our findings have implications for human health. Down the road people could be treated pharmacologically for low activity levels through drugs that targeted specific genes that promote activity. Pharmacological interventions in the future could make it more pleasurable for people to engage in voluntary exercise. Such interventions could also make it less comfortable for people to sit still for long periods of time," said Theodore Garland Jr., a professor of biology, whose laboratory conducted the multi-year research.
In humans, activity levels vary widely from couch-potato-style inactivity to highly active athletic endeavours.
Exercise physiologists define VO2 max as your maximal rate of oxygen consumption. It is a measure of your capacity to generate the energy required for endurance activities and is one of the most important factors determining your ability to exercise for longer than four to five minutes.
Your sedentary VO2 max value is primarily determined by genetics (a sedentary person may have a VO2 max value as high as 50 ml/kg/min. or as low as 20 ml/kg/min). Although anyone can improve their sedentary VO2 max value through training, this genetic variation helps explain why everyone can't train themselves to be elite.
"We have a huge epidemic of obesity in Western society, and yet we have little understanding of what determines variation among individuals for voluntary exercise levels," said Garland.
The study is an example of an 'experimental evolution' approach applied rigorously to a problem of biomedical relevance.
Although this approach is common with microbial systems and fruit flies, it has rarely been applied to vertebrates due to their longer generation times and greater costs of maintenance.
The results of such studies can inform biologists about fundamental evolutionary processes as well as 'how organisms work' in a way that may lead to new therapeutic strategies.
The study appears in the Proceedings of the Royal Society B.