Video: Water is super important to your health. While most of us know that we should be drinking enough water, you might not know what can happen to you body if you don't. This video breaks it down. As science news site DNews explains, a lack of water can cause all kinds of assorted health problems. Mild dehydration can impair focus, increase irritability and cause mood changes. As you lose more water without replacing it, your body will sweat less, your blood starts to thicken and your heart has to work harder to circulate blood. This can lead to more serious heart problems down the road. Check out the full video for more info.