Most people realise that drinking water is essential for maintaining good health. It keeps the immune system strong, moisturises skin and maintains energy levels. There is also a clear link between the amount of water you drink and your overall performance at work, when playing sports and in everyday life. When you stop off for a glass of the cold stuff at your office bottled water cooler, you infuse your body with essential H2O. It's essential because 70% of the human body is made from water and this natural ingredient is essential for enabling cells to interact with each other. The brain is made up of an even higher percentage of water – because it’s key to the electrical signals it uses to operate. It's an odd thought, but by staying hydrated, people can make sure they are performing to the best of their abilities. You'll know the feeling – when you're dehydrated and feeling fuzzy and lethargic, a cup of cold water from the water cooler can really perk you up again! Water is essential, too, for exercising, as it keeps muscles working as they should, lubricates joints and keeps the delicate salt and electrolyte balance in check. It's important to stay hydrated if you work in a physical profession or exercise regularly. Even if you swim for just a short period, you'll be losing lots of water – so never hit the gym or pool without a bottle by your side, or in your bag. Don't worry about buying expensive sports or energy drinks, though, as they will be packed with sugars. These sugars are quickly absorbed by the body, giving you a quick hit that rapidly fades away into nothing. Try adding a pinch of salt and sugar and maybe a little natural fruit juice to make your own sports drinks if you’re a fan of high-intensity workouts, or you exercise for long periods of time.