Aging is a natural process of all living organisms. In humans, it represents the accumulation of physical, psychological, and social changes that are thought of as an inevitable process of health decline. Aging doesn’t have to be that way. Recent publications have argued that the rate at which this decline occurs can be slowed or even reversed.
A growing number of scientists now believe that the first person to reach the age of 200 has already been born.

The idea of anyone living to that age is considered a fantasy by most people. Doing so in good health even more so. By slowing the aging process in human beings, we would also slow the natural decline associated with senescence and thereby extend into old age the health and functional capacity that is normally associated with youth.
David Sinclair is a professor of genetics and co-Director of the Paul F. Glenn Center for the Biology of Aging at Harvard Medical School. His work is trying to understand what causes aging and why we age.

Research done by Sinclair and many others have shown that the level of NAD+ declines with age.
They argue that the pace of aging is not inexorable or predetermined, but rather can be slowed and even reversed by a variety of approaches.

According to Sinclair, Sirtuins a family of seven proteins that affect the aging process, and are believed to do a lot of good things in our body are turned on by hormesis.
As part of the aging process, cells produce what is known as oxidants or free radicals which are toxic to cells and which can damage DNA and contribute to the aging process. Researchers in the field think that sirtuins can help prevent this kind of toxicity by speeding up the reaction by which harmful oxidants are neutralized in the body.