Staying hydrated seems simple enough—drink water when you’re thirsty and stop when you feel like you’re done, right? Well, it’s a bit more complicated than that, especially for runners.
That’s because not understanding the complicated equation of race distance and intensity combined with water and electrolyte intake can ruin a long run or race, not to mention have serious health repercussions. Drink too little and your ability to power through your workout suffers; drink too much and you can get sidelined by nausea and frequent pee breaks.
And even though you might first worry about dehydration for those summer runs, researchers found that the newer you are to running and the slower you run, the more likely it is that you will drink too much water while racing. (We’ll talk more about this later.)
To that end, much of the research demonstrates that mastering the art of hydration when you run isn’t as simple as it seems. Keep reading to find out if you drink water the wrong way—and how to drink water right.
6 Ways You Drink Water Wrong and 6 Ways to Drink Water Right
❌ Wrong Way: Gulping water during a race
✅ Right Way: Sip as you run
It’s okay to slow a little to make sure you’re getting in your fluids during a race, but gulping water at each aid station can ultimately slow you down and also lead to an upset stomach.
That’s because drinking too much water too quickly overloads the stomach, causing it to rapidly stretch. This can lead to discomfort and potential nausea, Justin Mullner, M.D., a board-certified primary care sports physician with the Orlando Health Jewett Orthopedic Institute in Florida tells Runner’s World.
Take small sips of water (or electrolyte drink) every 15 to 20 minutes, depending on the temperature and intensity of the run.
Combining a run with too much water is even more likely to cause nausea. That’s because intense exercise directs blood flow away from the stomach and toward the muscles, causing digestion to slow down. “So you put a bunch of water in there and the stomach really can’t handle it effectively and efficiently,” Mullner says.
A better strategy is to take small sips of water (or electrolyte drink) every 15 to 20 minutes, depending on the temperature and intensity of the run. “This approach helps maintain a steady level of hydration and prevents the stomach from becoming overly full,” Meghan Kennihan, a RRCA- and USATF-certified running coach, tells Runner’s World.
❌ Wrong Way: Drinking from a dirty water bottle
✅ Right Way: Regularly clean your bottle
Your trusty water bottle is always there when you need it. Sadly, constant use means you’re probably getting more than water. Unless you regularly clean your water bottle—which means daily according to Mullner—you could be getting a dose of bacteria or even mold.
Every time you put your mouth to the water bottle and use your hands to open and close it, you transfer bacteria that can make its way inside. The moist environment inside your water bottle provides an optimal breeding ground for bacteria and mold, especially if you live in hot, humid areas. If left unchecked, the bacteria and mold can continue growing, potentially causing you to experience symptoms similar to food poisoning (such as stomach pain or cramps, diarrhea, and vomiting), per the Centers for Disease Control and Prevention. People with mold sensitivities can have a flare-up of allergy symptoms.
Ideally, you’d wash out your reusable bottle—whether plastic, stainless steel, or glass—with soap and warm water each time, Mullner says. “It’s even more important if you’re using the bottle every single day or drinking beverages other than water,” he says. Mixing electrolyte powders or adding a sports drink to your bottle, for example, means more material for bacteria.
Signs your bottle could use a good scrubbing include visible residue, a funny or foul odor, or changes in how things taste, Mullner says.
❌ Wrong Way: Waiting too long to hydrate before a run or race
✅ Right Way: Start early
When preparing for a long run or race, many runners forget to hydrate until they’re practically toeing the starting line, “which is a bad idea because it doesn’t give the body enough time to absorb and utilize the fluids,” Kennihan says.
Staying well-hydrated in the days leading up to your long run or race can help you perform well, avoid feeling overly full, and reduce restroom stops. Be especially diligent about drinking water starting the day before a long run or race, and check your urine color to be sure you’re getting enough. “Really dark yellow is a sign that you’re not well-hydrated,” Mullner says. “Ideally, it has a slight tinge of yellow.”
Drink 16 to 20 ounces of water about 2 to 3 hours beforehand and then another 8 to 10 ounces 20 to 30 minutes before running.
Individual fluid needs vary. However, a general guideline for the day of the event is to drink 16 to 20 ounces of water about 2 to 3 hours beforehand and then another 8 to 10 ounces 20 to 30 minutes before running, Kennihan says. You may need to adjust your intake according to your body size, run distance, and outside temperature.
❌ Wrong Way: Drinking too much water on long runs
✅ Right Way: Balance electrolyte intake with water
It’s critical to drink enough water during long training runs and races. However, drinking lots of water, and only water, can lead to overhydration, meaning you have too much water in your body.
Hyponatremia is an extreme version of overhydration, and occurs when sodium levels in the blood are lower than recommended, leading to muscle cramps, headaches, nausea and vomiting, low energy, and confusion, per the Cleveland Clinic. Normally, your body keeps your electrolytes in balance by taking the minerals from the foods you eat and filtering the excess through your urine. However, intense exercise causes electrolytes (particularly sodium) to be quickly lost through sweat, and hot, humid temperatures only accelerate this loss, per the American College of Sports Medicine.
It's not just new runners who tend to overhydrate. At the other end of the spectrum, 41 out of 63 finishers at an ultramarathon also finished with mild or severe hyponatremia, according to a 2019 Frontiers in Nutrition study.
Take in electrolytes in addition to water if you’re running for longer than 60 minutes or in hot, humid temperatures.
Drinking water without replacing electrolytes dilutes the remaining electrolytes (again, sodium in particular) in your blood. “You can potentially get yourself into trouble with hyponatremia,” Mullner says.
To prevent an electrolyte imbalance, take in electrolytes in addition to water if you’re running for longer than 60 minutes or in hot, humid temperatures. Bring an electrolyte drink, some gels, or another electrolyte supplement.
❌ Wrong Way: Drinking a pure sports drink
✅ Right Way: Water it down
Sports drinks offer a convenient delivery system for carbs and electrolytes while running. Still, many runners prefer to water things down.
“Many sports drinks are too concentrated, leading to stomach cramps and nausea. Diluting them can still provide the necessary electrolytes and carbohydrates without overwhelming the stomach,” Kennihan notes.
The optimal ratio of sports drink to water depends on your preferences and the makeup of your drink. Mullner suggests diluting your sports drink to the point where it’s most palatable for you.
Diluting sports drinks can still provide the necessary electrolytes and carbohydrates without overwhelming the stomach.
The exception: Don’t dilute a sports drink that contains carbohydrates if you’re using it for energy purposes. “Some sports drinks have carbs in there to help extend the amount of time you can perform, and if you’re trying to absorb carbs better, you would have it with some electrolytes,” Mullner says. Adding water can cut down on how many carbs you get per sip, limiting performance benefits.
❌ Wrong Way: You don‘t know about your med’s side effects
✅ Right Way: You read labels and talk to your pharmacist
Some over-the-counter and prescription medications can affect an athlete’s hydration, says Kennihan. NSAIDs, such as ibuprofen and aspirin, can reduce blood flow to the kidneys, which can impair their ability to conserve water and electrolytes, potentially leading to dehydration, especially during prolonged physical activity like running.
Similarly, diuretics, which are prescribed for conditions such as hypertension and edema, increase urine production and promote the excretion of water and electrolytes from the body. Increased urine output can lead to a significant loss of fluids and electrolytes, making it easier for runners to become dehydrated, particularly in hot and humid conditions or during long-distance runs.
Likewise, antihistamines can reduce saliva production and increase the risk of dry mouth and dehydration, while laxatives can cause increased bowel movements and fluid loss.
Lastly, stimulant medications, such as those used for attention deficit hyperactivity disorder (ADHD), can increase sweating and fluid loss, potentially leading to dehydration if fluid intake is not adequately maintained.
Bottom line: As a runner, remember that hydration is as much a part of your performance as actual time on your feet.
The authors of a 2019 article published in the International Journal of Sport Nutrition and Exercise Metabolism recommended that runners develop a “personalized and practiced race plan” to optimize their fluid and carbohydrate intake based not only on their distance and intensity, but also taking into account their body composition, as well as the weather and other race conditions, such as refueling stations, at each event.
Lauren Bedosky
Lauren Bedosky is a freelance health and fitness writer who specializes in covering running and strength training topics. She writes for a variety of national publications, includingRunner’s World,Prevention, Experience LifeandWomen’s Running.
