It’s not rocket science but it fuels your whole body – WATER! Drinking 8-10 cups of water daily is key to keeping your kidneys, heart, joints, brain, digestion tract, and skin functioning at the optimum level. Staying hydrated when exercising or during the hottest days of summer is crucial to good health. Our body weight is over 50% water. Water is lost faster from our bodies when the weather is really hot and during exercise, in other words when we sweat profusely.