Did you know your body is 60 to 70 percent water? Blood is 90 percent water, the brain is 80 percent water, muscle is 75 percent water and bone is 13 percent water. If you want your blood flowing, your brain thinking and your muscles contracting, you need to keep hydrated.

In a worst-case scenario, you can only survive a few days without water. With the looming Texas heat upon us already, itÕs good to head into summer with an idea of how to manage your water balance.

You may think this is an easy task. After all, we all get thirsty, which in turn is our sign to drink. But did you know that by the time you get thirsty, you are already 3 percent dehydrated?

Some of the common symptoms of dehydration include fatigue, headache, thirst, nausea, light-headedness, dryness, a hot feeling and loss of urine production. If you exercise while dehydrated, your endurance and strength will also be impaired.

A physical examination may also show signs of:

• Low blood pressure
•  Blood pressure that drops when you go from lying down to standing up
• Rapid heart rate (above 100 beats a minute at rest)
• Poor skin turgor Ð the skin may lack its normal elasticity and sag back into position slowly when pinched up into a fold by the doctor; normally, skin springs right back into position.
• Delayed capillary refill
• Shock

Causes of dehydration:
You may be losing water too quickly. Water can be lost from sweating, hyperventilating, vomiting and urinating excessively (such as a diabetic might), as well as having diarrhea or fever.

How do you know how much water to drink each day? The needs are different for children and adults. For most adults, drinking 64 to 90 ounces (six 8-ounce glasses or four 16-ounce bottles) of water a day will take care of daily needs. Children are different in their water needs.

Their metabolism requires special attention when it comes to hydration. The childÕs weight is used to calculate water needs.

If your child weighs < 22 pounds (10 kg) = 1.5 to 2.0 ounces per pound (100 ml/kg)

If your child weighs between 22 to 44 pounds (10-20 kg) = 34 ounces for the first 22 pounds + 0.8 - 1.0 ounces for each pound over 22 pounds (1000 ml for 1st 10 kg + 50 ml /kg for each kg over 10 kg If your child weighs more than 44 pounds (>20 kg) = 50 ounces for the first 44 pounds + 0.3 ounces per pound over 44 pounds (1500 ml for 1st 20 kg + 20 ml/kg for each kg >20)

If you exercise, you should drink more water to account for sweat loss. A general guideline for fluid intake while exercising is as follows:

Before your workout:
eight to 16 ounces of water 15 to 30 minutes before exercise. Drinking a lot of water just before exercise can cause a water-log feeling and gastrointestinal distress.

During your workout:
four ounces every 15 minutes of exercise. After your workout: sixteen ounces within 30 minutes after exercise. Remember to hydrate throughout the day so you are not dehydrated the next day!

A more accurate way to determine your fluid needs when exercising is to calculate the fluids lost during exercise. This varies for every individual. In order to calculate lost fluid, you will need to know your pre- and post-exercise body weights and the amount of fluid you drink during exercise. To be most accurate, measure your body weight when you are naked.

Calculate fluid lost during exercise: (Body weight in pounds pre-exercise Ð Body weight in pounds post-exercise) x 16 ounces Calculate your total sweat loss: Fluid lost during exercise in ounces + fluid consumed during exercise in ounces Calculate your sweat rate: Total sweat loss / exercise duration Once you know your sweat rate, you can estimate your fluid needs for any duration of exercise.

Here are some tips to keep you hydrated during this hot summer: Drink fluids throughout the day rather than cramming them in all at once. Drink fluids between meals.

Drink alcohol in moderation. Alcohol will increase your chances of dehydration.

Use sports drinks, as well as water, during prolonged workouts to replace your electrolytes. As an added benefit, having carbohydrates in a sports drink can also benefit your sports performance.

Using these guidelines for water intake can help you prevent dehydration. But remember, your needs will change if you lose water from diarrhea, vomit, sweat or fever.

Is it possible to drink too much water? Yes! Actually, you can put yourself in a coma or cause a seizure by drinking too much water. Water will dilute your body, causing a salt imbalance. You can avoid this by taking in electrolyte drinks if you exercise for a prolonged period of time.

An easy guideline is that every third or fourth drink should be an electrolyte drink. But just as water needs vary, so do salt needs. So if you experience cramping on a regular basis when you exercise, you may need to increase your salt intake, as well.

For more information about hydration, visit ww.medicineinmotion.com.