Why Most of Your Body Is Younger Than You Are

When you take a sip of water it doesn’t just slake your thirst. It literally becomes you. The water that runs down your gullet will, within minutes and without processing of any kind, become some of the dominant fluid in your veins and your flesh. Most of your blood is simply tap water with cells, salts, and organic molecules floating in it. Some of the rubbery squishiness of your earlobe poured out of a bottle or a can just a short time ago. And much of the moisture in your eyes only recently fell from rainclouds. Your mouth is the portal through which water normally enters your body, but you are quite a leaky vessel. A hydrogen isotope study published in the British Journal of Sports Medicine reported that the sedentary men under examination consumed and lost about seven pints of body water per day, with four pints leaving through ...