Not drinking enough water can make it hard to think clearly and remember things.

When it's hot or you're exercising a lot, not drinking enough water can make you sick from the heat

Your body needs the right balance of water and salt to work well. Not having enough water can mess up this balance, causing muscle cramps, weakness, or a funny heartbeat.

Not drinking enough water can make your stomach upset and cause constipation or even more serious stomach problems.

When you're dehydrated, your body's defense system against germs weakens, making you more likely to get sick.

Not having enough water in your body can make your blood pressure drop, making you feel dizzy or even faint.

Even just a little bit of dehydration can make it hard to exercise. It can make you feel tired quickly and not as strong as usual.