How to stay hydrated on the run (especially when it's HOT!)



how to stay hydrated on the run while it's hot

As temperatures begin to rise, hydration should be at the front of every runner’s mind. Why is hydration important? What role do electrolytes play? How much should runners drink before, during, and after training? We’ll cover all this and more in today’s blog. Go ahead and grab a drink, because we’re about to dive in.

Why is hydration important for runners?

Water is found nearly everywhere in the body- cells, blood, organs, joints, muscles, and even bones. When runners consume enough water and are adequately hydrated, they can help ensure...

  • Improved recovery time from training and competition
  • Joint cushion and lubrication
  • Reduced risk of muscle cramps and injury
  • Body temperature regulation
  • Enhanced focus and concentration
  • Oxygen and nutrient delivery to cells
  • Effective removal of waste products
  • Efficient cardiovascular function
  • Less perceived exertion
  • Optimal performance and more


What happens when runners aren't adequately hydrated?

Runners typically lose fluid through breathing, sweating, and urinating. Runners lose about 1-4 lbs of fluid per hour when running. Even a 1% loss in body weight can negatively impact performance (that’s about 1.5 lbs in a 150 lb athlete), especially when in a warm environment. If proper rehydration doesn’t occur, runners may not only experience decreased performance but also run into more serious conditions like dehydration or hyponatremia. 

Dehydration occurs when more fluid is lost than is taken in. It is the more common hydration complication among athletes. Common symptoms include headaches, nausea, vomiting, cramping, dark-colored/smelly urine, and higher perceived exertion. 

Hyponatremia occurs when the body holds on to too much fluid and dilutes the level of sodium in the blood. With runners, it is usually caused by excessive fluid intake and not enough electrolytes. Symptoms include swelling of the hands/feet, stomach bloating, confusion, dizziness, vomiting, diarrhea, and seizures. People are more at risk for hyponatremia when they exercise for prolonged periods (think marathons) and excessively drink water before, during, and after their session. Females who are smaller, less lean, run slow, and sweat less are also more at risk, as well as those who regularly use NSAIDS (aspirin, ibuprofen). 

Both conditions should not be taken lightly and can result in death in some cases- be aware of the causes and symptoms not only for yourself, but also for your fellow running friends!

    hyponatremia and dehydration in runners

    How do electrolytes play a role in hydration?

    Electrolytes (such as sodium, chloride, potassium, calcium, and magnesium) are minerals found in the body that serve many important functions: regulating muscle contractions and nerve impulses, balancing blood pressure and pH levels, and helping the body maintain fluid balance through the process of osmosis. They are lost in sweat and urine, and are of concern to runners because substantial losses can result in severe muscle cramping or hyponatremia. Sodium and chloride are lost in the greatest amount.

    When it comes to meeting electrolyte needs, it’s important to remember that not all people sweat the same. Some individuals have a greater sweat rate than others, and some have saltier sweat. Those who sweat more and have saltier sweat (often characterized by white residue on skin/clothing after the sweat has dried) are more likely to experience large electrolyte losses.

    In order to meet electrolyte needs, runners can replenish losses from sweat and urine with sodium-containing sports beverages, salty foods (pretzels, pickles), or gels, gummies, and other sodium-containing sports nutrition products. They should also avoid overconsumption of fluids (ex: chugging water before/during/after training or competition). These practices are especially important for heavy/salty sweaters and those running for over two hours.

    Do runners need to add more salt to their diet?

    Although runners may lose extra salt via sweat, that doesn't automatically mean they need to add extra salt to their diet. Those who are heavy/salty sweaters, exercise for hours every day and/or in hot and humid conditions, or train in any other way that results in heavy sweating may need to add extra salt to their meals and snacks. It's important to note, however, that many Americans already exceed their daily sodium needs, so some athletes may not need to add extra sodium to their diet.

    electrolytes sources for runners

    How do heat and humidity influence hydration needs?

    Both high temperatures and high humidity increase the need for water and electrolytes. In extreme dry heat, the body loses fluid by producing sweat to help it cool down. Dry climates also speed up the process of water loss from breathing, and some water is even lost through the skin. In humid conditions, the high moisture content in the air means that sweat doesn’t evaporate as quickly to help cool runners down, and instead falls to the ground. The body responds by sweating profusely, causing runners to lose water and electrolytes. Individuals running in either of these conditions should pay extra close attention to their hydration needs.

    Runners can help maintain good hydration during the day by...

    • Drinking enough fluids so that their urine is a pale, straw color
    • Carrying a water bottle with them
    • Downloading a hydration tracking app (I recommend Plant Nanny)
    • Aiming to enjoy a glass of water with meals/snacks
    • Enjoying hydrating foods like watermelon, cucumber, bell peppers, oranges, fruit popsicles, and yogurt
    • Avoiding excess alcohol and caffeine, which are diuretics that can make individuals urinate more
    • Sipping on herbal tea before bed
    • Adding fresh fruit and herbs to enhance the flavor of their water
    • Enjoying sparkling water (keeping in mind that the bubbles may fill up their stomachs, which may make them feel less thirsty)

    urine color hydration chart for runners

    Runners can stay hydrated on the run by...


    • Beginning well hydrated with pale urine
    • Drinking 16-20 oz of water 2-3 hours before their run
    • Drinking another 8-12 oz 15-30 minutes before their run, especially if they anticipate there will be lots of sweating


    • Drinking enough water to avoid losing more than 2% of their body weight during a run, which can be prevented with the help of understanding their sweat rate (scroll to the bottom of this article for a how-to guide). Calculating sweat rate is not always necessary, but can be a useful tool for creating a hydration regimen
    • Runners who do not know their sweat rate can follow the general guideline to consume 3-8 oz of fluid every 15-20 minutes (one medium mouthful of fluid is about 1 oz)
    • Sipping on sports drinks or adding electrolytes if running for more than 60 minutes
    • Knowing where to find fluids (water fountains, stores/restaurants, trusted neighbors, etc)
    • Freezing half-filled water bottles, then filling the rest of the bottle up with water to take on their run
    • Carrying money to buy beverages in case of an emergency
    • Avoiding the urge to chug water before, during, and after exercise
    • Stopping to drink, if needed
    • Pinching the cups given out at races to make a spout for easier drinking. They can also fold the top of the cup over to carry it without excess spilling as they run

    Click HERE to see which water bottle we recommend for on the run


    • Drinking 16-24 oz of fluid for every lb of body weight lost
    • If dehydrated, pairing their water with sodium-containing foods or drinking sodium-containing beverages to help their body rehydrate. Examples include pretzels, pickles, crackers, salted fruits like watermelon, soups, chocolate milk, coconut water, or a fruit smoothie made with yogurt or milk.
    • Avoiding re-hydrating with alcohol, and being mindful of caffeine. Alcohol is a known diuretic that can cause them to urinate more (and halt rehydration). Caffeine is also a diuretic but has more mild effects compared to alcohol, especially for those who regularly consume it.

    how to stay hydrated on the run

    Runners may not feel thirsty, but that doesn’t mean they’re well hydrated. In some cases, thirst is perceived after dehydration has already occurred. Additionally, it’s important to consider that there are many distractions (music/audiobooks, busy surroundings, focusing on form/pace, etc) that can cause runners to miss or ignore their thirst signals.

    Bottom line: proper hydration is an important practice for runners, especially in hot and humid conditions. By enhancing hydration techniques before, during, and after a session, runners can continue to run strong and healthy.

    calculating sweat rate for runners

    Keep running strong with the Club Heldie app! Created with the help of registered dietitians, running coaches, and personal trainers, this app exists to help female runners of all capabilities and backgrounds achieve their biggest goals. Click HERE to learn more.


    • Karpinski, Christine, and Christine Rosenbloom. Sports Nutrition: a Handbook for Professionals: Sports, Cardiovascular, and Wellness Nutrition Dietetics Practice Group. 6th ed., Academy of Nutrition and Dietetics, 2017.


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