Scientists have identified a new sign of biological aging that may be reversible through simple exercise.

Most of us see aging as an inevitable process of life, but some scientists are beginning to consider it a disease that we can treat or at least delay.

“The idea that we could reverse aging is something that was long considered science fiction, but these findings do allow us to understand a lot more about the aging process,” said Riekelt Houtkooper, Professor of Translational Metabolism at Amsterdam University Medical Centre, said in a statement.

As we age, certain molecules begin to build up in our cells and contribute to their gradual decline. These molecules offer an enticing target for treating age-related diseases and aging in general. The only problem is, for the most part we don’t know what they are.

In a study published in the journal Nature Aging, Houtkooper and his Amsterdam University colleagues set about finding one of these aging-related molecules and potential methods for reversing its accumulation.