Just because you are dripping in sweat doesn't mean that you are OK. When you are coated in sweat, your body is not being effectively cooled by evaporation and you become more susceptible to overheating.

• How long can you survive without water? According to Dr. William Forgey, author of Wilderness Medicine: at 120 degrees Fahrenheit, you will live two days, at 90 degrees F, you can expect to live five to seven days, and at 60 degrees F, eight to ten days is the life expectancy.
  
  
• Cut out caffeine (tough for caffeine-heads used to hanging out in coffee bars sipping Lattes) and alcohol. Both are diuretics which remove valuable water from your system.
  
  
• Alergies or not, knock off the intake of antihistamines since they can block the nerves which stimulate sweating and if you don't sweat, your body is not able to cool itself which can lead to overheating and collapse--even if you are drinking plenty of water.
  
  
• Peek at your pee. That's right. When outdoors, it's no time to be bashful. Check the color of your urine output regularly as well as the frequency of nature's calling. If your body is producing relatively clear urine five times a day, you're fluid intake is fine. Cloudy or dark urine and an urge to purge of less than five times per day means you need to uptake the fluid intake.
  
  
• Experts suggest that on average, a hiker will consume approximately two gallons of water per person per day when the temperature sits around 100 degrees Fahrenheit -- and up to three to three and a half gallons as the Mercury climbs.
  
  
• In an emergency, when all looks hopeless, you can create enough water to stay alive with only a clear plastic bag and a few leaves. Chances are you have a clear, plastic baggie (the larger the better) in your pack. Place a handful of crushed or cut up leaves into the bag and then fill it with air and seal it--use string or the zip-lock closure. Place the bag on an incline, with the vegetation uphill, and in direct sunlight. Your evaporation still won't generate enough moisture to quench a raging thirst, but in a pinch it will keep you alive.