They’re essential to energy, focus, vitality, and metabolism. And yet most of us have no idea how our mitochondria work. Here’s how to tune up your body’s quadrillions of “energy factories” so you can perform at your peak. We spend billions of dollars every year buying pills, potions, and creams that promise to slow the aging process. But what if we could enlist our own bodies to help us live longer, healthier lives? Meet your mitochondria — the tiny factories in each of our cells that turn the food we eat and the oxygen we breathe into energy.