Drinking water is one of the most important things we can do for ourselves on a daily basis. Our bodies are roughly comprised of 70-75% water and are in constant need of replenishment. Throughout the course of the day as we carry out various physiological activities, our cells generate a metabolic waste product which, if left unchecked, will accumulate in our tissues and result in inflammation. What's the best way to clear this waste junk out of your system, you ask? Why, it's water! Think of it as an oil change, but on a much more regular basis - you're clearing out old, "dirty" liquid and replacing it with a new, fresh stock.
My patients often ask me how much water they need on any given day. The simple answer is that if you feel thirsty or your urine is dark, yellow, or cloudy, you need to be drinking a larger volume of water. The more complicated answer is: it depends. It depends on how physically active you are on that given day (if you have had an intense workout, you will need to drink more water), what kinds of foods you're eating (if you're eating salty foods, you need more water), your general physiological makeup (some people just need more water than others), and even the temperature and relative humidity (warmer and dryer = need more water). So that whole eight-glasses-of-water-a-day thing? It simply does not apply to everyone.
Finally, the water that you drink should generally be room temperature (read: NOT cold). There is absolutely no truth to the theory that cold water increases your metabolism because it requires the body to "work hard" to warm it up. Because room temperature water is closer to your physiological body temperature, it is more easily absorbed into your system than cold water - your body can use it more efficiently than it can cold water. Because of the large discrepancy in temperature between cold water (around 40°F, say) and 98.6°F, our bodies are unable to effectively hold onto and process cold water. It is for this reason that you will urinate more if you drink cold water in comparison to an equal volume of room temp water. Energetically speaking - and because acupuncture is an energetic medicine, after all - cold water inhibits the smooth flow of qi (or energy) in our bodies. Acupuncture is very interested in promoting this smooth, systemic, unobstructed flow. Room temperature water achieves this; cold water does not.