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How To Prevent Dehydration From Crushing Your Workout

You’ve got all you need to crush your run: a good pair of running shoes, comfortable athletic wear and an epic iTunes playlist. Unfortunately, the one thing you forgot that’s crucial to any successful workout is staying hydrated.

Whether you’re a weekend warrior or simply exercise for recreation, it’s important to stay hydrated. Good hydration means getting the right amount of water before, during and after exercise.

Don’t let dehydration crush your workout. Read on to learn how you can ensure your body performs at its highest level.

How does hydration fuel athletic performance?

A mere 2% reduction in fluids can result in a 10% to 20% decrease in performance. Between your heart-pumping exercise, sweat and lack of fluids, you can quickly go from hero to zero during your session.

“Perspiration is a key bodily function that helps keep your body relatively stable, making proper hydration critical to athletic performance,” said Nichole Reynolds, a certified athletic trainer at Banner Sports Medicine in Phoenix.

During exercise, your body can generate more heat than when you’re at rest. To counteract this, your body sweats to keep itself cool, but, in turn, this means you’re losing high levels of water.

Why is dehydration harmful?

“Staying hydrated before, during and after ensures you have plenty of fluids to replace sweat and prevents complications of dehydration, when the amount of water in your body falls below a normal, healthy level,” Reynolds said.

Dehydration can make it harder for your body to regulate heat, which can cause your body temperature to rise and your heart rate to increase. This causes you to feel more tired or fatigued.

Other tell-tale signs of dehydration are thirst, muscle cramps, dry mouth, dark-colored pee and nausea and dizziness. Severe dehydration can lead to heat stroke and even death if left untreated.

[Also read “Avoid Heat-Related Illnesses With These Tips.”]

How much water should I drink before exercising?

You may be a water champ during a workout, but it’s actually more important to hydrate   before your workout. Recommended amounts vary based on your height, weight, body composition, activity level and more, but many nutrition experts recommend 16 to 20 fluid ounces about four hours before exercise.

“Another way to determine if you’re well hydrated is to look at your urine,” Reynolds said. “Urine color should be light yellow like lemonade. If it’s dark yellow or amber, you may be dehydrated.”

How much water should I drink during a workout?

A common recommendation is to drink 7 to 10 ounces (or 4 to 6 gulps) every 15 to 20 minutes—and even more frequently when humidity or temperatures are higher. The general rule is: If you’re sweating, you need to be drinking fluids.

“The amount you sweat can vary from the person next to you,” Reynolds said. “It’s important for you to know how much you sweat for a given activity level (whether low, moderate or intense), in addition to how “salty” your sweat is, to determine hydration frequency and amount, including electrolyte replenishment.”

[Also read “How Far In Advance Should I Hydrate Before Exercise.”]

How much water should I drink after a workout?

After your workout, you’ll want to drink double the amount of water your body lost during exercise.

To figure this out, empty your bladder and weigh yourself prior to your workout. Then weigh yourself again at the end of your session in the same clothing. For each pound lost, about 16 to 24 ounces of water is recommended.

One easy way to keep your body hydrated is through solid foods that have lots of water in them already. Adding things like watermelon, celery, cucumber, etc., to your diet can keep your body hydrated and ready to go.

Do I need to drink as much water if it’s cold outside or I’m indoors?

“A common misconception is that you do not need to drink water if you are exercising indoors or when it is cold,” Reynolds said. “Regardless, exercise requires hydration, and sipping water throughout your workout is a good way to ensure you won’t be dehydrated.”

[If you’re headed out to exercise in the cold, check out these five tips to stay warm.]

Is it possible to drink too much water?

Yes! Drinking a bunch of water is never a good idea, no matter what kind of exercise you’re about to perform, since your body can only process a certain number of fluids at a time (roughly about half a liter per hour, or 16.9 ounces, the size of an average plastic water bottle). This is why being hydrated all day sets you up for a successful workout.

“Overhydration can be problematic and even life-threatening because our cells can only hold on to so much water,” Reynolds said. “To avoid overhydrating or underhydrating, it can be helpful to know your sweat rate by weighing yourself before and after a workout.”

[Also read “Busting Myths Behind How Much Water You Should Drink.”]

Do I need to replenish with electrolytes after every workout?

Maybe. Proper hydration also requires electrolytes, the minerals that are lost in sweat. These minerals include sodium, chloride, potassium and magnesium. “Electrolytes are responsible for regulating chemical processes in our body and fluid inside and outside of cells,” Reynolds said.

A regular gym session probably doesn’t require a sports drink but long-distance runners, triathletes or those who train with great intensity would do well to replenish their electrolytes.

However, some sports drinks can be high in sugar. Instead of a sports drink, coconut water is a great option, or you can eat fruits and vegetables that contain high proportions of water.

Will drinking extra water help with muscle soreness after working out?

A common misconception is that muscle soreness the day after a workout is because of lactic acid buildup and drinking extra water can help flush it out of your system and reduce pain. However, experts say excess lactic acid typically leaves your body within an hour after a workout.

“Post-workout soreness is called DOMS—an acronym for delayed onset muscle soreness,” Reynolds said. “This is actually caused by putting too much strain on your muscles during exercise and will usually last only 48 hours.”

Be sure to stretch before and after your workout to prevent any kind of injury.

[Also read “5 Tools to Relieve Muscle Soreness at Home.”]


By following a hydration plan, you will not only be able to prevent dehydration, but you’ll fuel your athletic performance. Make sure to follow these steps before, during and after each and every workout.

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