For young people, cells throughout the body are strong which translates into smooth and firm skin, shiny, full hair and lots of energy.
As the years pass, the strength of cells diminishes and they suffer breakage. Outwardly this is shown through wrinkles, grey hair and visible veins.
Exercise science professor Larry Tucker said: "Just because you're 40, doesn't mean you're 40 years old biologically.
"We all know people that seem younger than their actual age. The more physically active we are, the less biological aging takes place in our bodies."
The research found those who trained in high volumes compared to those who didn't or those who exercised less frequently had much longer telomeres, which are the protein endcaps of chromosomes.
The length of telomeres have a strong correlation with a person's age and over time the endcaps get shorter and shorter.
The longer the telomeres, the more they protect DNA from "fraying" and succumbing to disease. And the longer the telomeres, means for looking and feeling more youthful.
Telomeres serve as a guide as what causes aging and how much cells can renew. Cell renewal keeps tissues young and healthy.
For some, exercise may not work to slow down the hands of time.
Researchers from the University of California in Los Angeles claimed that some people are destined to die earlier, no matter their levels of physical activity or their lifestyle.
Through the study, they found five percent of people are genetically programmed to age faster and die younger than others.
Race may be another component on how cells age.
Latinos age slower than any other ethnicity according to researchers at UCLA.
They claim the group is unequivocally healthier due to cells taking much longer to age.
According to the Centers for Disease Control and Prevention, Latinos in the United States live an average of three years longer than Caucasians, with a life expectancy of 82 versus 79.
Physical activity has been linked to several other benefits which could increase lifespans.
Tucker said: "We know that regular physical activity helps to reduce mortality and prolong life, and now we know part of that advantage may be due to the preservation of telomeres."
Exercise has been found to ward off obesity and limit the risk of cardiovascular disease.
Despite the benefits of working out, statistics on regular physical activity in the nation are bleak; only about 20 percent of Americans get enough exercise and about 64 percent never do any physical activity at all.