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Liquids and Hydration for Athletes

Medically reviewed by Last updated on Jan 5, 2023.

Why is liquid important during exercise?

During exercise, your body temperature goes up and your body sweats. Your body loses water and electrolytes in your sweat. Electrolytes are minerals, such as sodium and potassium. You need to replace water and electrolytes lost in sweat to prevent dehydration. Drinking too little or much water can hurt your performance during exercise and sports competitions. Drink the right amount of water before, during, and after exercise to maintain the right balance of water in your body.

How much liquid should I drink?

Do not use thirst to decide whether you need to drink liquid. Thirst is not always a good sign that your body needs more liquid. It is a good idea to weigh yourself before and after exercise, especially during hot weather. This will tell you how much water you lost in sweat so you can replace this water after exercise.

  • Two hours before exercise, drink about 17 ounces of liquid. Drink 8 to 16 more ounces of liquid 30 minutes before exercise.
  • During exercise, drink at least 14 to 40 ounces of liquid every hour. The more you sweat, the more you should drink.
  • After exercise, drink 16 to 24 ounces of liquid for every pound lost during exercise.

What kind of liquid should I drink?

  • Drink water for exercise that lasts less than 1 hour. For exercise that lasts longer than 1 hour, drink liquid that has 4% to 8% carbohydrates to give you energy. This is about 10 to 19 grams of carbohydrates in a serving of 8 ounces. The liquid should also have sodium. Sodium can make drinks taste better and replace some of the sodium lost in your sweat. Sports drinks contain carbohydrates, sodium, potassium, and other ingredients that help you stay hydrated.
  • After exercise that lasts longer than 3 to 4 hours, replace sodium lost in your sweat. Eat salty foods and drink liquid that contains sodium.

How can I tell if I am drinking the right amount of liquid?

  • Your urine should be clear or very light yellow, with little or no smell. If your urine is dark or smells strong, you may not be drinking enough. Dehydration usually causes your mouth to feel dry. You will also feel very thirsty. You may urinate little or not at all. You may feel dizzy or confused. You may have a fast heartbeat and breathing.
  • Dehydration increases your risk for heat illness during hot weather. Stop exercising if you have signs or symptoms of heat illness. Some of these include weakness, muscle cramps, nausea, vomiting, headache, dizziness, or lightheadedness. Rest in a cool place and drink liquids.
  • If you are drinking too much liquid, you may feel tired and have nausea and a headache. The level of sodium in your blood may also decrease. If your sodium level is low, you may be confused and have trouble balancing. Drink liquid that contains sodium during exercise to prevent low sodium levels.

When should I contact my healthcare provider?

  • You have a fever.
  • You have nausea and are vomiting.
  • You have muscle cramps.
  • You have trouble keeping your balance.

When should I seek immediate care?

  • You urinate less or not at all.
  • You are confused and cannot think clearly.
  • You have a seizure.
  • You feel weak, dizzy, or faint.
  • You are breathing very fast or you have a very fast heartbeat.

Care Agreement

You have the right to help plan your care. Discuss treatment options with your healthcare provider to decide what care you want to receive. You always have the right to refuse treatment. The above information is an educational aid only. It is not intended as medical advice for individual conditions or treatments. Talk to your doctor, nurse or pharmacist before following any medical regimen to see if it is safe and effective for you.

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Further information

Always consult your healthcare provider to ensure the information displayed on this page applies to your personal circumstances.