What Doesn't Kill Us: How Freezing Water, Extreme Altitude, and Environmental Conditioning Will Renew Our Lost Evolutionary Strength

by Scott Carney

The body that you have isn’t too different from an ant colony. Long before animals ever appeared on earth, in a time when life comprised mostly single-celled organisms, microscopic bean-shaped bacteria called mitochondria flourished in the wild. These single-cell life-forms ate up oxygen from the environment and expelled an energy-rich waste product called adenosine triphosphate, or ATP. Over the course of millions of years, larger single-cell critters needed more energy to perform complex functions. Rather than develop a novel approach to creating ATP, they evolved to absorb mitochondria into their own cellular structures. Thus the first animal cells were born out of a symbiotic relationship. If you were to peer through a microscope into almost any cell in the body, you would find thousands of mitochondria sucking up oxygen and excreting ATP.