More than half of the human body is made up of water. We cannot survive without it.
When you lose more water than you take in, your body becomes dehydrated and cannot carry out its normal functions. Signs and symptoms of dehydration include thirst, headaches, fatigue, weakness, dizziness, irritability, weight loss, increased heart rate, low blood pressure, dry mouth and tongue, decreased urination, dark urine and constipation.
So how much water do you need to stay hydrated?
Sounds like a lot, right? But that total intake includes not only drinking water but also water from other beverages and food.
Food provides around 19 percent of our total daily water intake. Fruit, vegetables, soup, milk, diluted fruit juice and sports drinks are especially good sources of water. I suggest that most people dilute sugary fruit juices and sports drinks with water to avoid consuming too much sugar, partly because too much sugar isn't good for us but also because large amounts of sugar can contribute to diarrhea via osmosis. Pure sports drinks are fine for serious athletes but others should dilute them with at least half water.
Personally, I like water infused with fruit for a refreshing, non-caloric, hydrating beverage.
Many healthy people meet their fluid needs by allowing their thirst to guide them. However, using thirst as a guide is not really sufficient for athletes, people who are ill (diarrhea, vomiting, sweating), the elderly or anyone exposed to hot environments–all of whom should be hydrating regularly to meet their daily AI. The same goes for some people who have poor thirst sensations and never really feel thirsty.
To ensure you meet your AI for total water, I suggest you purchase a reusable water bottle to carry with you and refill it early and often.
For those prone to dehydration secondary to health issues (e.g. people with active inflammatory bowel disease or ileostomies) then you might want to talk to your health care provider about trying an oral rehydration solution.