Mitochondria are microscopic power generators that create fuel for cells. Small genetic mutations occur when they multiply. Normally these are corrected by specialized cellular repair systems. As mammals age, the mutations occur more frequently than the system can correct for and the mitochondria die.
Mitochondrion death is seen as a primary cause of old age. It causes “muscles to shrink, brain volume to drop, and hair to fall out”. These effects compound to create what we know as old age.
In a recent experiment, mice were genetically programmed to grow old at quicker pace. They lacked the mitochondrion repair system, so their mitochondria started to mutate and malfunction at an early age. After 8 months, the mice were frail “with spindly muscles, shrunken brains, enlarged hearts, shriveled gonads and patchy, graying fur”. All were dead before a year elapsed… except for the mice that exercised.
Half of the mice in this experiment had to run for 45 minutes, three times a week, at a pace similar to running a 50 minute 10k. After 8 months – when the non-running mice were near death – they were still youthful with “almost all of their muscle mass and brain volume [and] their gonads were normal, as were their hearts”. The running mice had more mitochondria, with fewer mutations, than the sedentary mice. None died.
The clear conclusion, according to the lead scientist, is that “exercise alters the course of aging”. This includes weight lifting, running, and endurance sports. With so much clear proof, there truly is no reason not to be getting daily exercise. Better hair, healthier heart, full-sized reproductive organs, where can you go wrong?
You can read more at the NY Times.