Your body is approximately 60% water. Your organs and all of your vital systems need water to function properly. Fatigue is one of the first signs of dehydration. A loss of just 1 – 2 percent of body weight as water is enough to cause body systems to slow down, causing you to feel sluggish, tired and irritable. If it turns into full-blown dehydration, it could cause an imbalance in electrolytes like sodium and potassium, which aid muscles and heart function.
How much water you drink depends on your activity level, weight and the weather conditions that you live in. Most doctors recommend 8-9 glasses per day, Although not all of your daily intake has to be water. Appoximately 20% can come from what you eat. Watermelon, cucumber and most other fruit and veges are obvious sources (One cup of watermelon has almost a full cup of water), but a lot of foods are wetter than you might think. Oatmeal and beans, even a chicken sandwich, have at least half a cup.
So if you need a quick pick me up, forget coffee, try drinking a glass of water or two.