What do marathon runners drink while running? A Complete Hydration Guide

January 11, 2026 •

4 min read

During a marathon, the human body can lose over 1.5 liters of sweat per hour, a significant amount that requires careful replenishment. To counter this and avoid dehydration-related performance drops, understanding exactly what do marathon runners drink while running is critical for success and safety.

Quick Summary

Marathon runners use a combination of plain water, carbohydrate-rich sports drinks, and electrolyte supplements to replace fluids and minerals lost through sweat, ensuring optimal energy and muscle function throughout the race.

Key Points

Combine Fluids for Endurance: Marathon hydration goes beyond water; it requires a strategic mix of water, sports drinks, and electrolytes to replace sweat losses and maintain performance.
Electrolytes are Critical: Minerals like sodium and potassium, lost through sweat, must be replaced to prevent muscle cramps and a dangerous electrolyte imbalance known as hyponatremia.
Individualize Your Strategy: Hydration needs vary greatly based on factors like body size, sweat rate, and race conditions, so personalize your plan through training.
Sip, Don't Gulp: Consuming small amounts of fluid frequently throughout the race is more effective and easier on the stomach than chugging large volumes.
Practice During Training: Never try a new drink or hydration strategy on race day; test everything during long training runs to avoid gastrointestinal issues.
Hydrate Before and After: Proper hydration begins days before the race and continues for hours afterward to aid in full recovery.

The Essentials: Water, Sports Drinks, and Electrolytes

For any marathon runner, hydration is a nuanced and crucial component of their race strategy. Simply drinking water is not enough for the prolonged demands of a marathon, as the body also loses vital electrolytes and depletes its carbohydrate stores. An effective hydration plan combines three key components to maintain performance and prevent cramping or exhaustion.

Plain Water

Water is the foundation of any hydration plan and is essential for cooling the body and transporting nutrients. For shorter runs (under 60 minutes), water alone is typically sufficient. However, during a marathon, consuming only plain water can dilute the body's sodium levels, a dangerous condition called hyponatremia. This is why other beverages become necessary.

Sports Drinks

Sports drinks serve a dual purpose for marathoners by providing both fluids and a source of carbohydrates for energy. These drinks contain glucose and fructose, which are easily digested and absorbed by the body to fuel muscles. Popular options include Gatorade, Powerade, and specialized endurance mixes like Tailwind, Maurten, or Skratch Labs. It is crucial for runners to test these drinks during training to ensure they don't cause stomach upset on race day. Most sports drinks are isotonic, meaning they have a similar carbohydrate concentration to the body's fluids, allowing for efficient rehydration. Other types, like hypotonic and hypertonic, serve different functions for faster absorption or higher carbohydrate load.

Electrolyte Replacements

When runners sweat, they lose electrolytes—minerals like sodium, potassium, and magnesium that are vital for muscle function, nerve signals, and maintaining fluid balance. For long races or heavy sweaters, sports drinks might not contain enough sodium to compensate for losses. In these cases, runners use electrolyte supplements such as tablets, chews, or salt capsules, which can be taken alongside plain water or a sports drink. Signs of being a "salty sweater" include white, salty streaks on clothing after a run, and these runners need to pay extra attention to their sodium intake. Some endurance athletes aim for 700-900mg of sodium per hour during a long race.

Hydration Strategy: When to Drink What

Beyond what to drink, the timing of fluid intake is equally critical. A smart hydration strategy starts before the race and continues systematically throughout.

Pre-Race Hydration

Staying well-hydrated in the 24-48 hours leading up to a marathon is vital. On race morning, runners should drink 16-20 ounces of water or a sports drink 2-3 hours before the start. A smaller amount, around 6-8 ounces, can be consumed 15 minutes before the gun goes off to top off fluid levels.

During the Race

During the marathon itself, the mantra is to drink little and often. Most experts recommend sipping 5-10 ounces of fluid every 15-20 minutes. This prevents the "sloshing" feeling in the stomach and ensures a steady supply of hydration and energy. Runners must experiment during training to find their personal sweet spot. Some alternate between water and sports drinks at aid stations, while others carry their own customized hydration mixes. Waiting until you feel thirsty often means you are already starting to dehydrate, which can negatively impact performance.

Post-Race Recovery

After crossing the finish line, rehydration is essential to help the body recover. Experts recommend consuming 1.5 times the fluid weight lost during the race within a few hours. This is also a good time to consume drinks that include carbohydrates and protein, which help replenish glycogen stores and repair muscles.

Hydration and Drink Comparison


Drink Type	Primary Benefit	Best For	Considerations
Plain Water	Basic rehydration	Shorter runs (<1 hr)	Lacks electrolytes and carbs for long distances; risk of hyponatremia
Sports Drinks	Replaces electrolytes and provides carbs	Long runs (>1 hr) and races	Contains carbohydrates and sodium; potential for stomach upset if not practiced
Electrolyte Tabs/Chews	Highly concentrated electrolytes	Heavy sweaters or long, hot races	No significant calories unless combined with gels/carbs; must be taken with water
Coconut Water	Natural source of potassium	Lighter activity or post-race	Often low in sodium, the most crucial electrolyte for runners

Conclusion

There is no one-size-fits-all answer to what marathon runners drink while running. The ideal strategy involves a personalized approach combining plain water, sports drinks for fuel and electrolytes, and supplementary electrolyte products for heavy sweaters or hot conditions. The key is to practice and fine-tune this hydration plan during long training runs to know exactly what your body needs and tolerates on race day. Listening to your body, consistently sipping, and never trying anything new on race day will ensure you're properly fueled and hydrated to run strong from start to finish. For further training and hydration tips, consider resources from reputable running organizations, like the New York Road Runners.

Frequently Asked Questions

No, during a marathon, plain water is not enough. You also need to replace the carbohydrates and electrolytes lost through sweat. Relying solely on water for long distances increases the risk of a dangerous condition called hyponatremia.

The main difference is that sports drinks contain carbohydrates for energy and electrolytes (like sodium and potassium) to replenish minerals lost in sweat, whereas water provides only fluid.

Electrolytes are essential minerals that help regulate muscle function, nerve signals, and fluid balance. Runners lose electrolytes like sodium through sweat and need to replace them to prevent cramping and maintain performance, especially in hot conditions.

It is recommended to drink small amounts of fluid frequently, typically 5-10 fluid ounces every 15-20 minutes, to maintain steady hydration and avoid stomach discomfort.

After a marathon, it is best to drink fluids that contain both carbohydrates and electrolytes. Some runners also opt for drinks with protein to aid in muscle repair and recovery.

A 'salty sweater' is a term for a runner who loses a high concentration of sodium in their sweat, often indicated by white streaks on their running clothes. If you are a salty sweater, you need to be more diligent about replacing sodium with electrolyte supplements during long runs.

Drinking a moderate amount of water or sports drink (16-20oz) a few hours before the race is recommended. However, drinking a large amount of fluid right before the start can lead to frequent urination or stomach issues during the race.