When temperatures hover around 100°F for days on end about the only thing I want to do is plunge into a refreshing pool of water.   This sudden urge to stay submerged led me to start thinking about the various roles water plays in our survival.  So no time like the present to review the importance of hydration and the best ways to stay hydrated.Water plays a key role in many of the body’s functions.  The human body is 60-70% water.  Water is crucial for digestion, lubrication, transportation and temperature control.  It is needed to get nutrients and oxygen to the body’s cells and keep skin healthy & smooth. Proper hydration is needed to maintain these essential functions; and even mild cases of dehydration can lead to low energy, loss of appetite, constipation & dry skin.So what’s the problem – drink some water, stay hydrated, right? Proper hydration is more of a challenge than you’d think.  Many times water is lost as quickly as it’s consumed.  It’s lost when we remove waste, sweat (& we sweat a lot when the temperature tops 100°F); even when we breathe.  We are also slow to react to thirst – often registering a level of dehydration before we are compelled to quench our thirst.  Dehydration is defined as fluid loss greater than 1% of body weight, with the possibility of fatal consequences with a 9 – 12% loss.So, how much water should we be drinking to stay properly hydrated?  The answer isn’t as easy as “drink at least eight (8-ounce) glasses a day”.  There is no shortage of ‘formulas’, recommendations & suggestions.  Based on the latest research the Institute of Medicine set adequate intake (AI) of total fluids for men at 3 liters (approximately 13 cups) a day, and for women it’s 2.2 liters (approximately 9 cups) a day (higher amounts are recommended for athletes).  But ideally hydration requirements need to take into account activity level, health and the weather.  This makes it difficult for a single formula or recommendation to fit everyone.  Obviously, when activity levels are high or temperatures soar fluid needs will be greater than when we’re lounging on the couch in the middle of winter.So, is drinking water the only way to avoid dehydration?  No, in reality all fluids count toward your daily total.  It’s estimated we meet about 80% of our water needs through the beverages we drink and about 20% through the foods we eat.  Any beverages that you drink can make up the balance of your daily water needs, even caffeinated & alcoholic drinks.  But there are advantages to making the majority of what you drink just water.  It’s readily available, calorie-free & inexpensive, and since we are 60-70% water it’s always best to replace any losses with the genuine article.So drink a glass or two of water at each meal, between each meal and before you feel thirsty and produce about 6 cups of pale-colored urine a day and chances are you are staying properly hydrated.  If you have any questions about your water intake, hydration level or health concerns check with your doctor or a registered dietitian.  They can help you determine the amount of water that is right for you.