The NYTimes reported on an extraordinary piece of research on exercise and aging by Dr. Mark Tarnopolsky, professor of pediatrics at McMaster University.

After genetically programming mice to age at an accelerated pace, Dr. Tarnopolsky demonstrated that exercise reduced or eliminated almost every negative effect of aging.

The rate of aging process is determined by our body’s ability to repair malfunctioning mitochondria. ‘Mitochondria combine oxygen and nutrients to create fuel for the cells’, acting as power generators. Our cells are constantly repairing malfunctioning mitochondria.

Eventually in the aging process, there are too many malfunctioning mitochondria  for our bodies to repair them all, leaving them to die. The physical responses to this process in humans is that our brain volume drops, our hair goes grey, muscles shrink and we appear old.

Dr. Tarnopolsky’s mice were bred with no mitochondrial repair mechanism, and developed signs of aging quickly. At the equivalent of 20 years in human terms, they were aging rapidly.