i hypothosize our souls eternal and between body spans we travel to stars as light or energy without matter to recharge ourselves with star light like you recharge a battery . then with soul full recharged we make attempts to become a sperm in a males body that can then attatch onto a womens egg which is needed to start growth of a new body with . the soul providing the energy that makes a bodys heart and nervoous system twitch , that energy absorbed out of stars . and reason our bodies age is because our souls run out of star light charge , obviously diet n exercise factors too but souls charge by far most important factor . but if you believe in this hypothosis of mine quest becomes how to recharge the soul with star light while still maintaing a body on your self / soul . figure out how to recharge soul and you shall become able to make your body last forever