This paper is written about research showing how various habits and activities can affect a human's heart and liver. The first studies on human DNA dosage and the effect of age were held and evaluated in 1975. These were expanded to include 29 individual human hearts (Strehler) and validated in 1979. A direct link has also been drawn between smoking, heart and liver damage by a team of researchers at the Medical College of Wisconsin, Milwaukee. It is popular knowledge that smoking indirectly causes heart attack by interfering with blood supply. It is also a toxin, which is inhaled into the body and is to be eliminated by the liver.