David Sinclair has been reverse-engineering the aging process for two decades. As the co-director of the Paul F. Glenn Center for the Biology of Aging at Harvard Medical School, Sinclair and his colleagues have identified several key enzymes and interactions inside cells that cause them to “lose their identity” over time, making our bodies more susceptible to diseases like cancer, heart disease, and dementia. But what if aging itself is the real disease? “Aging is the one disease that we all get if we live long enough,” Sinclair told Seeker. “I define it as a disease. Most doctors are trained that aging is something separate from disease.