Even if you don't have an accident, swimming while sick may readily pollute the water. Lakes and rivers can also be polluted by animal waste, sewage spills, and runoff from heavy rains. You might become ill if you drink polluted water. If you are swimming in a lake or ocean and feel sick afterward, stop swimming and float on your back with your arms over the side of the boat. This will help you regain your sense of balance and avoid further injury. Do not eat or drink anything while you are trying to recover your balance, as this could cause you to lose it even more. If you are feeling better after you recover from your illness, then go ahead and eat and drink again. But remember that contaminated food and water can lead to serious health problems if you're not careful. Be sure to wash your hands thoroughly after being in the water, and don't eat or drink anything else until at least 30 minutes after you last drank water. Also beware of hidden dangers when swimming in dirty water. There can be parasites in dirty water that can infect anyone who drinks it. These include roundworms, hookworms, and tapeworms. The most common way for these parasites to enter our bodies is through our mouth when we eat food that has been contaminated by dog feces.