We are 70% water. If our water drops to the point of dehydration, our bodies stop functioning. So, if you're out on a hot day, working, exercising or hiking, drink water before you get thirsty. How much you drink depends on what you're doing. But keep it regular, every 1-2 hours. Balance your fluids and food. Keep an eye on the kids.

The general idea is drink water. But it is more complicated than that. Stick to clear liquids like water or a broth. If you've got an oral rehydration solution, use that, but always read the packaging for guidance. And avoid diuretics — things that make you pee — like alcohol, coffee and tea, and sugary stuff like soft and sports drinks. They can cause diarrhea and make you lose even more fluids.

Whether it's just you, or a child or an older person you're with, check yourself and them. Are you irritable or restless? Do they have sunken eyes, a rapid pulse, or are they drinking really, really fast? Pinch the skin. Does it go back slowly? Is your pee dark? Does it have a bad odor? Or does your breath smell? Well, then, there may be some level of dehydration. It's time to get help.

Now the real danger signs: Are you or the person you're with lethargic or unconscious? Is their pulse absent or weak? Can you sense any respiratory distress? Are they wheezing, grunting, breathing rapidly, sweating, flaring their nose? And think about those early signs: Sunken eyes and dry skin that doesn't spring back when you pinch it. When you're already dehydrated it gets difficult to drink.

It can happen to any of us. But babies, children and elderly people have a higher risk of dehydration. Diuretic medicines for reducing fluids or blood pressure can make dehydration more likely, as can some diabetes drugs. Check with your doctor. And, if you're with kids, check for drowsiness, fever, a dry or sticky tongue or mouth, crying without tears, or a dry diaper over three or more hours.

It takes more than water. You need to replenish fluids, sugars, electrolytes — minerals like sodium, potassium, calcium, chloride, and phosphate that help the body and mind function. For mild cases, you may be able to take an oral rehydration solution. Other quick fixes: Fruits, vegetables, salty snacks and some say milk. In severe cases, you may need to be treated by a doctor or even in hospital.

We still take water for granted in the richer nations. It's a luxury that people in poorer nations don't have — 1 in 3 people in the world lack access to clean water, and, in some of the least-developed countries, even health care facilities lack water service. Those are often the hottest places on Earth, making it tough for people to stay hydrated and healthy. Same for you if you're visiting.

Drinking too much water can lead to overhydration, and that can be as bad as dehydration. It happens when your kidneys fail to process the fluid in your body. That can lead to low sodium levels, or hyponatremia. Sodium regulates the fluids in and around your cells. And if that fails, overhydration can cause fatal brain swelling. So, if your pee is always clear, hold back, you're drinking too much.