Fluids and Hydration

How important are fluids?

Fluid replacement is probably the most important nutritional
concern for athletes. Approximately 60% of your body weight is
water. As you exercise, fluid is lost through your skin as sweat and
through your lungs when you breathe. If this fluid is not replaced
at regular intervals during exercise, you can become dehydrated.

When you are dehydrated, you have a smaller volume of blood
circulating through your body. Consequently, the amount of blood
your heart pumps with each beat decreases and your exercising
muscles do not receive enough oxygen from your blood. Soon
exhaustion sets in and your athletic performance suffers.

If you have lost as little as 2% of your body weight due to
dehydration, it can adversely affect your athletic performance. For
example, if you are a 150-pound athlete and you lose 3 pounds
during a workout, your performance will start to suffer unless you
replace the fluid you have lost. Proper fluid replacement is the key
to preventing dehydration and reducing the risk of heat injury
during training and competition.

How can I prevent dehydration?

The best way to prevent dehydration is to maintain body fluid
levels by drinking plenty of fluids before, during, and after a
workout or race. Often athletes are not aware that they are losing
body fluid or that their performance is being impacted by

If you are not sure how much fluid to drink, you can monitor your
hydration using one of these methods.

1.Weight: Weigh yourself before practice and again after practice.
For every pound you lose during the workout you will need to
drink 2 cups of fluid to rehydrate your body.

2.Urine color: Check the color of your urine. If it is a dark gold color
like apple juice, you are dehydrated. If you are well hydrated, the
color of your urine will look like pale lemonade.

Thirst is not an accurate indicator of how much fluid you have lost.
If you wait until you are thirsty to replenish body fluids, then you
are already dehydrated. Most people do not become thirsty until
they have lost more than 2% of their body weight. And if you only
drink enough to quench your thirst, you may still be dehydrated.

Keep a water bottle available when working out and drink as often
as you want, ideally every 15 to 30 minutes. High school and junior
high school athletes can bring a water bottle to school and drink
between classes and during breaks so they show up at workouts

What about sport drinks?

Researchers have found that sports drinks containing between 6%
and 8% carbohydrate (sugars) are absorbed into the body as
rapidly as water and can provide energy to working muscles that
water cannot. This extra energy can delay fatigue and possibly
improve performance, particularly if the sport lasts longer than 1
hour. If you drink a sports drink, you can maintain your blood
sugar level even when the sugar stored in your muscles (glycogen)
is running low. This allows your body to continue to produce
energy at a high rate.

Drinks containing less than 5% carbohydrate do not provide
enough energy to improve your performance. So, athletes who
dilute sports drink are most likely not getting enough energy from
their drink to maintain a good blood sugar level. Drinking
beverages that exceed a 10% carbohydrate level (most soda pop
and some fruit juices) often have negative side effects such as
abdominal cramps, nausea, and diarrhea and can hurt your

What does the sodium in sports drinks do?

Sodium is an electrolyte needed to help maintain proper fluid
balance in your body. Sodium helps your body absorb and retain
more water. Researchers have found that the fluid from an 8-ounce
serving of a sports drink with 6% carbohydrates (sugars) and
about 110 mg of sodium absorbs into your body faster than plain

Some parents, coaches, and athletes are concerned that sports
drinks may contain too much sodium. However, most sports drinks
are actually low in sodium. An 8-ounce serving of Gatorade has a
sodium content similar to a cup of 2% milk. Most Americans do get
too much sodium, but usually from eating convenience-type foods,
not from sports drinks.

What are guidelines for fluid replacement?

•Drink a sports drink containing 6% to 8% carbohydrate to help
give you more energy during intense training and long workouts.
To figure out the percentage of carbohydrate in your drink use the
following formula:

grams of carbohydrate/serving

-------------------------------------------- X 100 = % of carbohydrate in

mL of drink/serving

For example, 240 mL (a 1 cup serving) of