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COLUMBIA - It’s hot. It’s muggy. It’s Missouri in July! Of course, we’re going to be sweating a lot, right? You hear every fitness professional around asking the same question: “Are you drinking enough water?” But what happens if you drink too much?

Just like anything else, too much of a good thing can (sometimes) be bad. And, believe it or not, there is such a thing as overhydration. It can be rare but it does exist.

Mild Symptoms of Overhydration

  • Nausea and vomiting
  • Headache
  • Changes in mental state (confusion or disorientation)
  • Bloating (you're retaining water!)

Severe Symptoms of Overhydration

Overhydration can lead to dangerously low levels of sodium in the blood (doctors call it hyponatremia). This can cause super-severe symptoms.

  • Muscle weakness, spasms, or cramps
  • Seizures
  • Unconsciousness
  • Coma
  • Death

How Can Overhydration Be Prevented?

  • Weigh yourself. Endurance athletes should weigh themselves before and after a race to determine how much water they have lost and how much they need to replenish.
  • Know your limits. One liter per hour is the maximum!
  • Pace your hydration. Running a half or full marathon or competing in an endurance event? Hydrate properly before and during your exercise to avoid overhydration postevent. Sip, don't chug! For everyday water drinking, sip slowly, and often.
  • Balance with sports drinks. Again, don't overdo this one, but mixing in a sports drink to your hydration will help you replace electrolytes, sodium, and potassium — these things are lost in sweat, but not replaced with water.
  • Stay in tune with your body. Pay attention to how much you urinate and its color.
  • Talk to your doctor. If you are experiencing excessive thirst or a strong urge to drink water that seems unusual, contact your doctor.

So what is the correct amount of water to drink each day?

The Institute of Medicine determined that an adequate intake (AI) for men is roughly about 13 cups (3 liters) of total beverages a day. The AI for women is about 9 cups (2.2 liters) of total beverages a day.

You may need to adjust this amount based on some of the following factors:

Exercise. If you exercise or engage in any activity that makes you sweat, you need to drink extra water to compensate for the fluid loss. An extra 1.5 to 2.5 cups of water should suffice for short bouts of exercise, but intense exercise lasting more than an hour requires more. How much more depends on how much you sweat during exercise, and the duration and type of exercise.

Intense exercise. During long bouts of intense exercise, it's best to use a sports drink that contains sodium, as this will help replace sodium lost in sweat and reduce the chances of developing hyponatremia, which can be life-threatening. Also, continue to replace fluids after you're finished exercising.

Environment. Hot or humid weather can make you sweat and requires additional intake of fluid. Heated indoor air also can cause your skin to lose moisture during wintertime. Further, altitudes greater than 8,200 feet (2,500 meters) may trigger increased urination and more rapid breathing, which use up more of your fluid reserves.

Illnesses or health conditions. When you have fever, vomiting or diarrhea, your body loses additional fluids. In these cases, you should drink more water. In some cases, your doctor may recommend something like Gatorade, Powerade or CeraLyte. You may also need increased fluid intake if you develop certain conditions, including bladder infections or urinary tract stones. On the other hand, some conditions, such as heart failure and some types of kidney, liver and adrenal diseases, may impair excretion of water and even require that you limit your fluid intake.

Pregnancy or breast-feeding. Women who are pregnant or breast-feeding need additional fluids to stay hydrated. Large amounts of fluid are used especially when nursing. The Institute of Medicine recommends that pregnant women drink about 10 cups (2.3 liters) of fluids daily and women who breast-feed consume about 13 cups (3.1 liters ) of fluids a day.