Exercise is the key to a fit and healthy life, and it wards off potentially life-threatening afflictions, such as heart disease.

That said, taking up routine bike riding, running and gym workouts can be hard to commit to, even though new studies show that exercise changes DNA, the shape and performance of genes, which is vital when seeking improved fitness and health.

New research shows that the human genomes are dynamic and complex, and genes perpetually switch on and off contingent on biochemical signals received from the body. And when genes are switched on, they produce proteins that encourage physiological reactions somewhere else in the body.

Whether active or quiet, scientists recognize genes bustle about as a result of exercise, but scientists are unsure as to how those genes respond to exercise. The process of chemical reactions to genes and its effect on DNA is called epigenetics, and it occurs outside of the gene -- mainly through a practice called methylation.

Methylation responds to biochemical signals, and its patterns change in response to lifestyle. Exposure to pollutants and commitment to certain diets, for instance, can shift methylation patterns on some of the genes in one's DNA, affecting which proteins are expressed by genes. And depending on the genes involved, it can affect the likelihood of health risks and the risk of disease.

Little is known about the relation of exercise and methylation. There've been a few studies conducted that address how single bouts of exercise may or may not lead to instantaneous changes in the methylation patterns of particular genes in muscle cells. But little attention has been focused on whether longer-term, routine physical training affects methylation. And if so, how?

Scientists at the Karolinska Institute in Stockholm scientists published a research study that recruited 23 healthy young men and women. The young men and women were brought into the lab, and they endured a number of physical performances and medical tests, including a muscle biopsy. They were also asked to exercise half of their lower bodies for an unprecedented three months.   

The reason for this particular method is to address the obstacles frequented when studying epigenetic changes. It's difficult to isolate the effects of exercise from behaviors and diets because so many aspects of one's life affect methylation patterns.

Karolinska's scientists circumvented obstacles by having volunteers bicycle using only a single leg, while leaving the other leg untrained. Each person became his or her own control group, where both legs experienced methylation patterns swayed by his or her entire life. The 45-minute one-legged pedaling, done at a moderate pace, four times per week for three months, demonstrated changes related to exercise.

Muscle biopsies and other tests were administered following the research period, and as expected, it showed that one leg was more powerful than the other and displayed physical superiority.

DNA changes were more intriguing, however, as they're constantly in the process of mutation. Sophisticated genomic analysis was used by researchers to determine that more than 5,000 sites on the genome of muscle cells from the exercised leg now featured new methylation patterns. The changes were significant, showing more methyl groups, and those changes were not found in the unexercised leg.

An abundance of methylation changes were on portions of the genome known as enhancers, which amplifies gene-protein expression and changes in thousands of the muscle-cell genes. And the genes in questions often play a role in insulin response, energy metabolism and muscle inflammation.

In layman's terms, it affects the health and fitness of muscles and the entire body. The convoluted process has shown the importance of exercise, made evident by the documented genetic changes and shifts in methylation patterns and gene expression depending on fitness.

For Latinos, in particular, not only can exercise improve quality of life, but it also can alter likelihood of developing diseases and illnesses Latinos are predisposed to, such as diabetes, fatty liver disease, lung disease, eye disease, Alzheimer's disease, mild cognitive impairment, obesity, heart disease, womb cancer, strokes and other health challenges.