There are actually many ways to do it. One is to eat healthy and do non-stressful exercises like walking. Live a rewarding life such as being in a functional community.

If you want to get technical at the medical and science world then look up the special enzymes called Telormerase. These are certain enzymes that is known to extend the telomeres.

This is only half the story. I believe there are many other conditions involved at this process such as compassion.