Answers to All of Your Running Hydration Questions (2024)

Often times, food gets most of the attention when it comes to maintaining energy for your runs and your life. And of course you need carbs (plus protein and fat) to keep running mile after mile, but another must-have for staying in prime shape is simple yet crucial: water.

Determining exactly how to hydrate for running can seem a little confusing, especially when it comes to drinking up before, during, and after your workouts.

To get the details, Runner’s World asked Heather Milton, M.S., C.S.C.S., an exercise physiologist and clinical specialist at NYU Langone’s Sports Performance Center and Katie Kissane, R.D., C.S.S.D., at Fuel to Run in Fort Collins, Colorado to break down everything you need to know about running hydration.

How much water do you need to hydrate your runs?

As a baseline, the Institute of Medicine (IOM) suggests the total daily water intake (from fluids and water-containing foods) for men and women ages 19 to 50 years is approximately 3.7 liters (or 125 fluid ounces) and 2.7 liters (91 ounces) per day, respectively.

To meet that quota, Kissane suggests starting with about 16 to 20 ounces in the morning to rehydrate after a night of sleep, and then continue to drink fluids through the day to prevent the onset of dehydration. If that seems excessive, remember that most fluids (not just water) count toward your daily goal, as does fluid from water-containing foods like fruits and vegetables. Feeling thirsty might also be an indication that you are already dehydrated.

“I also do not recommend drinking excessive amounts in the evening as this may cause the athlete to wake up to pee several times at night,” Kissane says.

Also, everyone’s kidney function is different, so spacing fluids out throughout the day helps to maintain healthy kidneys, Milton says. One way to help facilitate this would be filling a water bottle that holds roughly 20 ounces and drinking half of that each hour.

You also have to consider how much fluid is consumed in other beverages like teas and coffee. Fresh foods also have higher water content than dried or processed items, and all count toward your daily intake. An individual who eats all fresh foods with tons of vegetables at meals may need to drink less water than someone who eats microwave dinners for meals, Milton says.

Should your pee actually be clear?

“Nope, light yellow is appropriate. Clear is an indication of possibly too much water intake,” Milton says.

One thing to keep in mind: Medications and some foods can change the color of urine, so if you are on antimalarials, antibiotics, or a number of other medications, these simple color rules may not apply.

Should runners drink more than the recommended amount?

Yes, athletes do need to consume more than the recommended amount on training days. They can start with the 91- to 125-ounce recommendation and add fluids according to how long they are training. Each athlete’s needs are different, and it can be difficult to determine exactly how much more water to drink, because things like altitude, heat, and humidity can affect how much fluid is lost through sweat, Kissane says.

One way to see how much additional fluid you need is by determining your sweat rate. To do that, weigh yourself before and after a one-hour workout, and drink 16 to 20 ounces of fluids per pound that you lost.

“[Weighing yourself] may not be feasible, so I always encourage an athlete to consume fluids throughout the day and monitor their urine,” Kissane says. If urine is slightly yellow, that’s a sign that you’re hydrated. If it is dark yellow, you need to drink!

How much water should you drink before exercise?

Ideally, you’ve already been hydrating throughout the day, so having about 16 to 20 ounces in one to two hours prior to exercise should be good—but don’t chug water immediately before heading out the door for a run, because it might make you feel full, Kissane says.

“Try not to drink so much water before exercise that the stomach is distended,” Milton adds.

On a long run, how often should you stop for water breaks?

A general rule of thumb is to drink about four to five ounces every 15 minutes of exercise, but again, that varies depending on the individual, and the type and intensity of exercise, says Milton.

What are the dangers of being dehydrated?

When you’re running outside, especially in the heat, dehydration can make it more likely that someone would succumb to heat stroke. Dehydration may also contribute to painful muscle cramping, which can impact athletic performance.

If an athlete drinks an excessive amounts of water without replacing electrolytes, they can cause a dilution of electrolytes in the body, which can lead to a dangerous condition called hyponatremia (low sodium levels in the blood), Kissane explains.

Someone is doing moderate to intense exercise in hot and/or humid environments for an hour or longer should consider having an electrolyte drink before or during exercise and possibly afterward for rehydration, adds Kissane.

Another option is to consume something salty, such as pretzels, before the workout and have it with fluids.

What are the dangers of being too hydrated?

Overhydration can lead to exercise-associated hyponatremia, which means you have too much water and not enough sodium in your blood. Symptoms of hyponatremia include nausea and vomiting, headache, confusion, and muscle weakness or cramps. If hyponatremia becomes severe, there is risk for seizures, coma, and even death.

A recent study published in Wilderness and Environmental Medicine found that to help avoid hyponatremia, you should consume sodium or salty snacks along with fluids, and drink to thirst—being careful not to drink too much.

You’ll want to be careful not to consume too much sodium as you work out, as it can contribute to dehydration symptoms. The best thing to do is have a sports drink with electrolytes and avoid very high sodium supplements. Also, using your “sodium appetite,” or taste for salt, can help regulate intake when drinking or eating salty foods.

How do you know if you’re hydrated?

“If your urine is straw- or lemonade-colored [pale yellow], you are usually good. You can also tell by the frequency of urination. If you are [using the bathroom] every few hours, that is a good sign,” Milton says.

Another way is to check your skin. If you pinch your arm and the skin snaps back quickly, it is a sign of better hydration, Milton adds.