There are many factors in deciding how much water is needed to fully hydrate your body. Size and mass have a lot to determining it but so does the activities you choose to do. The old rule of 8 servings of 8 ounce glasses is a good start but the intensity of your day will determine if you may need to supplement it with more.
The main factors in calculating necessary water consumption is height, weight, age and daily activities. Gender is not a major factor. For example: a 5'5" 130lbs 18 year old person on a low intensity day could manage the basic 8x8 regiment. While a 6'2" 190lbs 30 year old should probably supplement their day with an extra serving. If you were planning on going for a high-intensity run for 30 minutes your body is constantly losing water through attrition and sweat, and could require an extra 20+ ounces of water just to replace what you've lost.
Water is a main key towards good health. Cold water has even been shown to increase your metabolism and aid in weight loss in combination with a low-sodium diet. Dehydration can immediately lead to negative mental and health functions so never let youself become even mildly dehydrated.
The main points are to listen to your body, especially during times of exercise. It is very easy to dehydrate and much harder to over-hydrate. So if you find yourself dizzy, or sweating a lot, or even if your environment is hotter than normal, just go ahead and quench your thirst while continue to regularly drink water through your day. Check out our selection of Leak-proof Stainless Steel Water Bottles to take your water on the go.