New research from Brigham Young University in Utah has revealed that exercise can effectively slow the aging process. According to the study, vigorous exercise may be able to slow down a type of aging that occurs at the cellular level.

“Just because you’re 40, doesn’t mean you’re 40 years old biologically,” exercise science professor Larry Tucker told Science Daily. “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 study, published in Preventative Medicine, focused exclusively on telomeres as signs of cellular aging. Telomeres are the small protein end-caps on chromosomes and they act as a sort of biological clock. Each time a cell replicates, a tiny fragment of telomere is lost. So as a person ages, their telomeres get progressively shorter.

Tucker and his team analyzed data from a total of 5,823 participants in the CDC’s National Health and Nutrition Examination Survey. This particular survey housed the perfect data set, as it’s one of the few indexes that actually includes telomere length for each subject. What the data revealed was surprising, to say the least.

Researchers found that individuals who practice high levels of physical activity on a regular basis have telomeres significantly longer than the average person’s. Even individuals who were moderately active didn’t exhibit telomeres as long as those people who exercised vigorously and regularly.

“If you want to see a real difference in slowing your biological aging, it appears that a little exercise won’t cut it,” Tucker said. “You have to work out regularly at high levels.”

Although this discovery is remarkable, Tucker and his team still aren’t sure exactly how exercise works to preserve telomeres. Tucker said the phenomenon may be tied to a combination of inflammation and oxidative stress. Both of these factors have been linked to telomere length, and Tucker’s theory is that exercise can help relieve both of them over time.

Exercise has been linked to longevity for quite some time, but this new research reveals that you’ll really have to sweat if you want to reap all of the benefits. For the 95% of Americans who own and exercise in t-shirts, that means a lot more laundry, but it also may contribute a longer, healthier life.

“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,” Tucker said.