Underlying mechanisms behind regular exercise benefits

It helps improve overall health and prevent disease. But the reasons why exercise does that haven't been fully understood.

Enter Zhen Yan, professor with the Fralin Biomedical Research Institute at VTC and the College of Agriculture and Life Sciences at Virginia Tech, who helped discover thousands of alterations in bodies after various durations of endurance exercise training.

The Molecular Transducers of Physical Activity Consortium, of which Yan is a founding member, studied both male and female rats over eight weeks of endurance exercise and found thousands of molecular alterations. These findings, which published in May in Nature, have implications for human health, such as in liver disease, bowel disease, cardiovascular health, and tissue recovery.

"For most people in most situations, exercise is better than medicine," said Yan, who is also director of the Fralin Biomedical Research Institute's Center for Exercise Medicine Research and vice chairman of the International Research Group on Biochemistry of Exercise. "This data suggests that exercise can be a very potent and profound protection against diseases, such as nonalcoholic fatty liver disease, inflammatory bowel disease, and many others. This study unveiled things that we did not know, and I think it's the beginning of revealing significant impacts of exercise in how it promotes health and prevents diseases."

The National Institutes of Health funded the research. In addition to Yan, the study's authors include Sarah Lessard, who in July will join the Fralin Biomedical Research Institute and the Department of Human Nutrition, Foods, and Exercise in the College of Agriculture and Life Sciences.

Is exercise better than medicine?

The Molecular Transducers of Physical Activity Consortium studied male and female rats over eight weeks of endurance exercise, examining changes in blood, plasma, and 18 solid tissues. Researchers analyzed nearly 10,000 samples using 25 molecular platforms at four training stages.

They found thousands of molecular changes, with differences between sexes in multiple tissues. These changes included regulation of immune, metabolic, stress responses, and mitochondrial pathways relevant to human health issues like nonalcoholic fatty liver disease, inflammatory bowel disease, cardiovascular health, and tissue recovery. Mitochondria are often referred to as the powerhouse of a cell as they aid in chemical energy as well as the regulation of a cell cycle, cell growth, and cellular health.

No single medicine could have such positive system-wide impacts and is as long-lasting, Yan said.

"Impact of exercise is far better than any single medicine," he said. "There are studies showing that pregnancy exercise can even positively affect the grandchildren, and no single drug can do that."

The path ahead

For Yan and the Molecular Transducers of Physical Activity Consortium, this research opened new doors. First is the need to expand the research to resistance-based exercise training -- which could be weightlifting, resistance bands, or other methods of building muscle mass.

But it's also important to truly understand the factors that mediate the molecular alterations.

"We need to dissect the health benefits that we've found so far," Yan said. "I proposed a study that will analyze protein factors in the blood that are released by organs and tissues, such as the adrenal gland, muscles, and the heart, in response to a single bout of exercise and exercise training."

Are these protein factors, or humoral factors, the true player in mediating the health benefit of exercise? How do they orchestrate coordinated cellular, biochemical and molecular responses in their target tissues and organs in achieving the superb health benefits of regular exercise?

Those are the burning questions, Yan said.

And those that he intends to answer.