Hydration: What Every Runner Should Know


Water makes up about 55% to 78% of your body. When you sweat a lot, your body’s water level decreases and affects normal bodily functions.

Running is one of the physical activities that can cause one to sweat. So, if you plan to compete in a running race or marathon, ensure you stay adequately hydrated.

If you experience dehydration or have an underlying medical condition that makes you sweat excessively, consider dropping by a medical clinic for consultation. This site may help you locate a healthcare facility near you.

Why is hydration important when running a marathon? How much fluid is needed to stay hydrated throughout the race course? Aside from water, are there other recommended hydration options for runners?

This article explains the importance of hydration in running activities and how runners can stay hydrated during a run. This write-up also discusses how much fluid to take and the various hydration options available to runners.

The Importance of Hydrating When Running

Hydration is essential whether you're an amateur runner occasionally running to stay fit or a serious athlete participating in competitions. Proper hydration involves drinking sufficient water before, during, and after physical activity.

Water aids in the following essential body functions:

  • Digestion
  • Joint lubrication
  • Oxygen delivery
  • Temperature regulation
  • Chemical balance

If you don’t drink enough fluids, you can become dehydrated, which can lead to numerous symptoms like:

  • Headaches, dizziness, and lightheadedness
  • Tiredness or fatigue
  • Dry mouth
  • Low blood pressure but high heart rate
  • Appetite loss
  • Muscle cramps
  • Flushed or red skin
  • Constipation

These symptoms can become complications when you’re running and even cause you not to finish the race. Drink sufficient water and keep yourself hydrated to minimize or prevent such conditions from interrupting your run.

Tips on How to Stay Hydrated During a Run

If your next workout or race event occurs less than 12 hours away, consider prehydrating about four hours before the event starts.

Some experts suggest consuming five to seven milliliters (ml) of fluid per kilogram (kg) of your body weight. This amount equals one large glass for an average individual weighing 75 kgs.

While there are runners who drink insufficient amounts of water and experience dehydration or its symptoms, some individuals drink too much. Excess water intake can lead to problems like stomach sloshing or hyponatremia (low sodium levels in the blood).

How Much Fluid to Take to Stay Hydrated

Each individual has different fluid requirements, so there are no hard and fast rules for how much fluid to take while running or exercising.

The factors you need to consider when determining how much fluid to drink are the following:

  • Your sweat rate
  • Environmental heat and humidity
  • Duration of the activity
  • How hard you are exercising

The American Council on Exercise suggests the following guidelines when drinking water before, during, and after exercising:

  • Consume about 17 to 20 ounces of water two to three hours before exercising.
  • Drink eight ounces of water during warm-up or 20 to 30 minutes before you start exercising.
  • Take 7 to 10 ounces of water every 10 to 20 minutes during the activity.
  • Drink eight ounces of water within 30 minutes after exercising.

Some athletes measure their fluid loss during exercise to determine how much water to take. In this case, one recommendation is to drink 16 to 24 ounces of water per pound of lost body weight.

Hydration Choices for Runners

Runners have the following options to rehydrate before, during, and after a run:

  • Water: Plain water is a readily accessible source for regular daily hydration. Many athletes and recreational exercisers still consider plain water sufficient for hydration, especially for activities that are:
    • Moderate in intensity
    • Less than one hour long
    • In low humidity and cool temperatures
  • Sports drinks: A sports drink may be helpful if you’re performing high-intensity exercises for longer than an hour.

Sports drinks usually have the necessary calories, potassium, and other nutrients that can provide energy and electrolytes (minerals with an electric charge) to help you perform for extended periods.

Choose your sports drinks carefully, as some contain high-calorie levels from the added sugar or high sodium levels.

Other sports drinks contain caffeine. Drinking too much caffeine can cause a diuretic effect on your body.

Diuretics typically aid in removing sodium and water from your body. This function means you may need to urinate more often, causing further fluid loss.

  • Electrolyte hydration: When you start sweating more due to higher temperatures or prolonged and more intense workouts, you may need to switch from plain water to electrolytes.

Electrolytes can come in the following forms:

  • Pre-mixed drinks
  • Capsules taken as a supplement
  • Chewable tablets
  • Powders or tablets mixed with plain water
  • Electrolytes mixed into edibles such as energy gels and chews

The electrolyte product you choose will depend on your running intensity, hydration needs, taste preferences, and how you’ll hydrate during your run.

Different electrolyte replacement products have varying formulations. For example, some brands have more sodium, while others have higher potassium levels.

If you’re unsure of what electrolyte product to take, consult your doctor to get an evaluation of your fluid intake needs.

You should also talk to a running or fitness expert to help design a running program and recommend the appropriate fluid intake for such activities.


  1. Dehydration


  1. Hydration for Athletes


  1. Diuretics