How Much Should I Drink While Running?

Fluid intake while running is of great importance, as it significantly affects a runner’s performance, health, and overall well-being.

The right amount and type of fluid can help optimize performance and minimize health risks.

In this article, HDsports explains various aspects of fluid intake while running, including when and how much you should drink, especially during long runs and under different weather conditions.

During which runs do I not need to drink?

For short runs lasting less than 30 minutes, it is generally not necessary to consume fluids during the run. The body has sufficient reserves to manage this time span without additional fluid intake, especially if the runner is well hydrated before the run. Studies show that during a short, intense effort, the body does not yet reach a critical state of dehydration.

Well-trained runners can also complete longer sessions of up to about one and a half to two hours without fluid intake. Especially during base training runs of up to 90 minutes, it is often sufficient for experienced runners to drink before and after the workout.

When should I start drinking while running?

Once the duration of the run exceeds 30 minutes, particularly during intense efforts, it becomes advisable to consume fluids. From about 45 to 60 minutes onward, you should begin drinking small amounts of water regularly. A guideline from the American College of Sports Medicine recommends drinking about 150 to 300 milliliters every 15 to 20 minutes to prevent dehydration.

However, well-trained runners can go longer without fluids. Temperature is also an influencing factor. More on that below.

How much should you drink during a marathon?

During a marathon, which typically lasts 3 to 5 hours for recreational runners, fluid intake is particularly critical. Drinking too little can lead to dehydration, while excessive fluid intake can cause hyponatremia (a dangerously low sodium concentration in the blood). A study recommends drinking about 400 to 800 milliliters of fluid per hour during a marathon, depending on individual factors such as body size, sweat rate, and weather conditions.

More on marathon nutrition: Marathon nutrition plan: Everything you need to know about fueling during a marathon!

Should you drink more in hot temperatures?

In high temperatures, fluid requirements increase significantly because the body sweats more to regulate body temperature. It is recommended to increase fluid intake accordingly. A study by the National Athletic Trainers' Association recommends increasing fluid intake by up to 50% when temperatures exceed 25 degrees Celsius.

This may mean that runners in hot conditions should drink up to 1.2 liters per hour to compensate for increased fluid loss. However, the truly optimal amount of fluid also depends on performance level and individual needs. In most cases, almost no runner actually requires the maximum of 1.2 liters per hour.

Which beverages are recommended while running?

Water is usually sufficient for short to medium-length runs. For longer runs and especially for marathons, electrolyte drinks or sports drinks are advantageous, as they provide not only fluids but also important salts (such as sodium and potassium) as well as carbohydrates. These components help maintain electrolyte balance and provide energy.

Studies have shown that sports drinks can improve performance in endurance events by replenishing glycogen stores and delaying muscle fatigue.

How much should runners drink before and after running?

Preparation for a run begins before the starting signal. Runners should ensure they are well hydrated by drinking sufficient fluids in the hours before the run. A general recommendation is to drink about 400 to 600 milliliters of water or a sports drink 2 to 3 hours before the run and another 200 to 300 milliliters shortly before the start. However, you should not drink too much, as this may require a bathroom break during the race in the worst case.

After the run, rehydration is crucial to replace lost fluids and electrolytes. A rule of thumb states that you should drink about 1.5 times as much fluid as you lost during the run. This can be estimated by weighing yourself before and after the run; for every kilogram of body weight lost, about 1.5 liters of fluid should be consumed.

What options are there for carrying fluids while running?

There are various methods for carrying fluids while running:

• Handheld bottles: Easily accessible and well suited for shorter runs.
• Hydration belts: Equipped with several small bottles, they offer a balanced solution for medium-length runs. However, they are not recommended in races, as you carry extra weight for the entire distance.
• Hydration packs: For long runs beyond the marathon distance, these backpacks with integrated drinking systems are ideal, as they hold larger amounts of fluid and make drinking easier while running. However, they also add extra weight, which can reduce performance.
• Refreshment stations: In organized races such as marathons, there are refreshment stations along the course where runners can take in fluids and snacks. In a well-organized marathon, recreational runners therefore definitely do not need hydration belts or backpacks.

Each method has its advantages and disadvantages, and the choice depends on personal preference and the length of the run. It is important to test your chosen method before race day to ensure it works well and is comfortable.

Conclusion and Summary

Proper fluid intake is an essential part of running training and competition. Runners should be aware of when and how much they need to drink in order to maximize performance and minimize health risks. Especially during long runs and under extreme weather conditions, it is important to have a well-thought-out hydration plan. Water and sports drinks play a central role, and the choice of hydration method should be based on individual needs and preferences. By taking hydration seriously and planning accordingly, runners can make their runs safer and more enjoyable.