Water accounts for 60 per cent of our bodies, and is essential to every cell. So it's not too surprising that new research has found that college students who took water with them into an exam scored higher marks than their counterparts who didn't.
Other research has suggested that staying hydrated keeps the memory sharp, mood stable and motivation intact. You can also think through a problem more easily.
Staying hydrated doesn't just impact your brain though. Here are a few ways water benefits your body's health.
* Water keeps your throat and lips moist, and prevents your mouth from feeling dry. Dry mouth can cause bad breath and/or an unpleasant taste, and can even promote tooth cavities.
* Dehydration lowers your blood volume, so your heart must work harder to pump the reduced amount of blood and get enough oxygen to your cells, which makes everyday activities like walking up stairs, as well as actual exercise, more difficult.
* It keeps your body cool. Your body releases heat by expanding blood vessels close to the skin's surface - this is why your face gets red during exercise - resulting in more blood flow and more heat dissipated into the air. When you're dehydrated, however, it takes a higher environmental temperature to trigger blood vessels to widen, so you stay hotter.
* It helps muscles and joints work better. When you're well hydrated, the water inside and outside the cells of contracting muscles provides adequate nutrients and removes waste efficiently so you perform better. Water is also important for lubricating joints. Contrary to popular belief, muscle cramps do not appear to be related to dehydration, but to muscle fatigue.
* When we are severely dehydrated our skin is less elastic. This is different from dry skin, which is usually the result of soap, hot water and exposure to dry air. However, sadly, drinking lots of water won't prevent wrinkles.
* Water helps cleanse your body, inside and out. Your kidneys need water to filter waste from the blood and excrete it in urine. Keeping hydrated may also help prevent urinary tract infections and kidney stones. If you are severely dehydrated, your kidneys may stop working, causing toxins to build up in your body.
You don't have to take your water au naturale, however. Some might prefer it in the form of tea, although too much tea may hinder the absorption of essential nutrients like iron. And there is also a chance that it will become an addiction.
Adding milk to it may reduce the quantity of antioxidants, making an otherwise healthy drink a source of inflammation and acidity, while too much black tea (and therefore caffeine) can cause side effects including headache, nervousness, sleep problems, vomiting, diarrhoea, irritability, irregular heartbeat, tremors, heartburn, dizziness, ringing in the ears, convulsions and confusion.
However, regular tea consumption may lower the risk of contracting Alzheimer's and other neurodegenerative diseases, research having established that drinking green and black tea improves cognitive scores among those with dementia.
The combination of caffeine and L-theanine in tea has been shown to improve reaction time, visual processing, memory and concentration. It even changes the way your brain is organised for more efficient information processing.