This theory originated with Denham Harman proposing that oxidative damage to the mitochondrial DNA results in a loss of energy resources and eventual cell death. Early reviews of the involvement of mitochondria in aging include Strehler, B.L., 1977, pp 243-247 and Miquel, 1980 . Further updates are by Miquel in Miquel, 1982 , Miquel, 1983 and Miquel, 1992 . A major expansion of the ideas of mitochondrial DNA damage theories were provided by Linnane and Ozawa, 1989. They proposed that oxidative damage to the mitochondrial DNA results in a loss of energy resources and that clinical interventions could counteract this process. Evidence would seem to indicate that, with increasing age, there is an increase in DNA damage and a decline in mitochondrial activity (respiratory function) in post-mitotic (non-dividing) cells, e.g. heart and kidney cells. This could result in a shortage of energy which increases the probability of these cell dying in stressful conditions.