Next time you're tempted to skip the gym, consider this: recent research into the epigenetic effects of exercise suggests that workout sessions can do more than just get your abs in shape. They can act as a virtual time machine to keep both your body and mind younger.

"As you train, your cells release molecules into the bloodstream that create epigenetic switches to turn many different genes throughout the body on or off, including genes related to aging," Marcus Bamman, PhD, Director of UAB's Center for Exercise, said. "We've known for some time that aerobic exercise as well as strength and endurance training have positive health benefits, and now we are learning the molecular underpinnings of how it happens."

In response to exercise, nutrition, environment, chemical stresses and other cues, clusters of methyl atoms attach to genes, making them more or less able to receive and respond to biochemical signals. Swedish researchers found new methylation patterns in more than 5,000 sites on the genome of muscle cells during a recent study of the epigenetic effects of exercise.

"What is particularly intriguing is that in addition to physical performance, researchers are also reporting improvements in memory, cognition and mood," Bamman said.

As Bamman was quoted in a Time magazine article last year, "exercise is medicine." He went on to discuss UAB's participation as one of 12 research centers selected by the NIH to explore what conditions this particular type of medicine might help to treat.

"The epigenetic effects of exercise are a big part of the MoTrPAC (Molecular Transducers of Physical Activity in Humans) study," Bamman said. "We are cataloging biological molecules affected by exercise and mapping out the molecular changes that occur so we can get a better understanding of the benefits of physical activity, the underlying mechanisms, and how to use them to improve health."

Now beginning the second year of the six-year study, MoTrPAC is recruiting a total of 2700 healthy adults and will compare blood and tissue samples before and after exercise to a sedentary control group. Mapping will work to identify molecular signals that transmit the health effects of physical activity and how they are altered by age, sex, body composition, fitness level and exposure to exercise.

"We are looking at all genes to see how they are modified, which could help us discover new targets for treatment," Bamman said. "We're collecting samples to identify short term and long term changes. Down the road, we hope to find genes sensitive to exercise that might help us to modulate hypertension, heart disease, diabetes, and other diseases of aging.

"The data I've seen so far is compelling, particularly in regard to learning and memory. We want to understand the mechanisms of how activity increases the release of molecules like BDNF ( Brain Derived Neurotrophic Factor.) Maybe exercise can help us delay cognitive decline and give people more years to enjoy their quality of life."

Bamman and UAB's Center for Exercise Medicine are also working on another study regarding the epigenetics of exercise.

"The PHITE (Precision High-Intensity Training through Epigenetics) program is being funded by the Department of Defense and what we learn could be helpful to everyone," he said. "We're working to identify training methods that modify epigenetic responses and to characterize how epigenetic changes regulate physiological processes, pathways and mechanisms associated with both moderate and high intensity training. We hope to identify real-time biomarkers of cardiorespiratory and neuromuscular performance that predict physical training outcomes. That could help us learn how to train more effectively with less risk of injury.

One of the major questions in the concept of exercise as medicine is how to prescribe it.

"It isn't enough for clinicians to tell patients to simply get more exercise," Bamman said. "We need to determine dosage--how much activity, how long, how intense and what type for what disorder."

Compliance might also be a problem when prescribing exercise. This could be improved when patients understand the specific health benefits.

"Exercise has value for people of all ages. Pregnant women who exercise actually pass on epigenetic benefits to their babies," Bamman said. "And we've learned that older people can exercise with greater intensity than most people realize - in fact, they are the ones who benefit most."