It should be simple. If you run in the heat, drink more water. But figuring out how much to drink and when while running in hot weather can be complicated. Enter electrolytes and it’s downright confusing. I got you though with some straightforward hydration tips for summer running.
Hydrating while running in the summer heat is important because your body uses water from your blood for sweat to cool your body. If your blood doesn’t have enough water, it gets thicker, and can’t get oxygen to your muscles as fast—causing you to slow down. If you don’t have enough water to sweat, then you can overheat which can be life-threatening.
Along with water you need electrolytes. Electrolytes are a key component for hydration because they help regulate your body’s water balance allowing your muscles to retain the right amount so they can operate properly.
And like with everything—you can have too much of a good thing. Drinking too much water while running or taking in too many electrolytes while running can be harmful to your health and even fatal.
Factors affecting hydration
How much water and electrolytes runners need can vary widely from runner to runner and run to run. Hydration needs are affected by factors such as:
- Air temperature
- Run duration
- Run intensity
- Fitness level
- Genetics, and
However, there are general rules of thumb for hydration. Using these guidelines plus experimentation during your training can help you nail your hydration needs. (P.S. I had a great conversation about this on The Passionate Runner podcast with registered dietitian Megan Robinson).
In this article, I’m going to cover:
- How much water do you need to drink while running in the heat
- How many electrolytes do runners need while running in the summer
- Dangers of drinking too much water and having too many electrolytes
- A summer running hydration guide
- Summer hydration tips for runners, plus
- A review of the 5 best electrolyte drinks for runners
So, let’s get moving!
Related: 7 Ways to Recover Faster from a Marathon
How much water should I drink while running in the heat?
How much water you should drink while running in high heat depends on the variables above. However, the below guidelines from registered dietitian Amy Stephens can help you figure out what your body needs to stay hydrated and perform well.
Note: These guidelines are for runs longer than 60 minutes. If your run is shorter than an hour, then you likely don’t need to drink more than you regularly do or intake more electrolytes (unless it is VERY hot).
Related: The Best Energy Gels for Your Marathon
- Before your run: Two hours before your run, aim to drink 16 to 18 ounces. Four hours before your run, shoot for 16 to 24 ounces of water. Aim to drink at least 400 mg of electrolytes (sodium) in these fluids.
- During your run: Aim for 2 to 5 ounces of fluid (or two big gulps) every 10 minutes of running. Shoot for 400 mg of sodium an hour.
- After your run: Ideally, you will have weighed yourself before your run (and before you hydrated) to know your pre-run weight. Aim to drink 16-24 ounces per pound of body weight lost. Aim for at least 400 mg of sodium after your run.
Related: Marathon Fueling 101: What Runners Should Eat
Stephens notes, “The goal is to start the exercise hydrated, then maintain hydration as much as you can. Oftentimes, athletes start dehydrated and then focus on catching up.”
Can you drink too much water?
Yes, you can drink too much water. This is called hyponatremia and can be fatal. Hyponatremia means your blood is too diluted and you don’t have enough of the electrolyte sodium. This can cause fatal nerve and heart issues.
Signs of hyponatremia include:
- Nausea and vomiting
- Loss of energy, drowsiness, and fatigue
- Restlessness and irritability
- Muscle weakness, spasms, or cramps
- In serious conditions, seizures and coma can occur.
The main signs of dehydration include:
- Irregular heartbeat
- Mental confusion
Related: How to Get Used to Running in the Heat
What are electrolytes?
Electrolytes are minerals in your body that have an electric charge. They can be found in your blood, urine, tissues, and other body fluids.
Electrolytes help with
- nerve signaling
- muscle contractions
- bone health
- pH level balance
- water balance in your body
- the elimination of waste from your cells
- and make sure your nerves, muscles, heart, and brain function correctly.
How many electrolytes should I drink while running?
In an hour of running, the average person loses about:
- 800-1,000 mg of sodium
- 195 mg of potassium
- 20 mg of calcium, and
- 10 mg of magnesium per hour
Related: How to Carbo-load for a Marathon
It’s recommended that runners aim to replace about 50 to 80 percent of those losses while running for runs lasting longer than an hour.
So, if you are running for two hours, aim to intake a total of 800 mg of sodium, about 200 mg of calcium, 20 mg of calcium, and 10 mg of magnesium.
Considering the average sports drink like Gatorade has about 200 mg of sodium, that would mean you need to drink two sports drinks an hour. That’s a lot sloshing around in your stomach.
There are better options and I’m going to get to that below.
Related: How to Get Used to Running in the Heat
Can you have too many electrolytes?
Yes, you can intake too many electrolytes.
Symptoms of electrolyte imbalance include:
- headaches, and
- fast heart rate
So, how can I tell how many electrolytes do I need?
You can go to a lab and get your blood or urine tested to find out your electrolyte needs. There are also DIY tests you can do. Or. you can use the below hydration guide and tweak it to meet your needs.
If you use 400 mg an hour as a starting point bear in mind:
- It’s helpful to weigh yourself before your runs so you know how much you lose.
- It’s also helpful to pay attention to your body’s response to exercise: Are you a heavy sweater? Do you salt marks on your body post-run? These could be signs you need to ingest more water and electrolytes than the general guidelines.
Related: The 10 Best Supplements for Runners
Hydration Guide for Runners
Easy runs in under an hour. No need to consume more electrolytes or water than usual. It’s always a good idea to stay hydrated and eat a balanced diet. You can have a sports drink with breakfast or add some salt to your toast.
Runs lasting 1 to 3 hours. Aim to drink about 16 ounces of fluid with about 400 up to 1,000 of sodium before your run depending on the elements and intensity. Aim to intake about 400 mg of sodium an hour of exercise. If you eat a balanced diet, you don’t need to focus on taking in potassium, magnesium, or chloride. The sports drinks will have those electrolytes as well.
Runs more 3+ hours. Continue to take in 400 mg an hour of running. If your effort is intense, you may need more but your stomach may not be able to handle it. Salt tablets like SI Caps can come in handy during this time.
Post-run. After your runs, intake a sports drinks to recover the weight you lost—about 16 ounces per pound plus water. You can also stick with water and eat salty foods including pizza and chips. Add salt or take electrolyte tablets.
Related: The Scientific Benefits of the Long Run
How can I tell if I am getting enough electrolytes or fluids while running?
If you follow the guidelines of aiming for about 400 mg of sodium and about 16 ounces of fluids an hour and you don’t experience any of the symptoms above such as cramping or nausea, then your nutrition is on point.
Remember your needs will vary based on variables such as weather, altitude, and workout intensity.
Hydration Tips for Summer Running
- Drink early and often. Drink an electrolyte drink before your run. And, then keep it up, especially for runs lasting longer than an hour. Sip on a sports drink throughout. Ideally, you will be drinking up to 16 ounces an hour during your run.
- Plan your electrolytes. You want to take in about 400 electrolytes an hour. So do the math before your training run or race:
- How many electrolytes are in your energy gels? How many are in your sports drink? Do you need to supplement with salt tabs?
- Experiment with what combination works best for you during your training. Bear in mind that while you will want to aim to hit 400 mg an hour of sodium—you may need a bit or less.
- Weigh yourself. Be sure to weigh yourself before and after your runs to get an idea of what your hydration and electrolyte needs are. This will help you figure out how many bottles and how many milligrams of salt you need per hour of running. This will also help you rehydrate appropriately, helping you recover faster from your runs. So, when you get in the door. Weigh yourself and then start drinking!
- Plan ahead. Think about how you will carry your hydration on your training runs and during race day. Some people like hydration packs or hydration vests. Others prefer to carry two handheld water bottles.I stash my bottles along my running route. On race day, I use the race’s water stops. This is because I do not like carrying things—especially when running at an intense effort.
- Don’t go overboard. You can over-hydrate and have too many electrolytes. Overhydrating can be deadly. And having too many electrolytes can wreak havoc your stomach. So, if you take salt tabs, for example, drink water with them!
Thus, nailing your hydration for running may be a performance-enhancer but it can also be a lifesaver!
Related: 3 Proven Ways to Refuel from a Long Run (+ 2 Yummy Recipes)
The 5 Best Electrolyte Drinks for Runners
Now, looking at these numbers may stress you out—how can I drink that much while running? Thankfully, there are electrolyte products available that make hydrating while running easy.
Here are the 5 best electrolyte drinks for runners available today. Note that I focus on the sodium contents as that electrolyte is the one that is most lost while running and the hardest to replenish. All these products include the other crucial electrolytes for runners.
Gnarly Nutrition products are NSF-certifiably CLEAN. Their main endurance mixes provide electrolytes and vitamins to help you perform better and recover faster. The below products are powder mixes that you scoop into a bottle and shake.
Gnarly Hydrate Electrolyte Mix. This mix is Gnarly’s classic electrolyte mix formulated to optimally replace the fluid and electrolytes you lose when you sweat and is loaded with electrolytes and B vitamins to fuel tough runs. It has just enough sugar to effectively transport vitamins and electrolytes without being overpowering.
Sodium: 250mg. Mix with 12-16 ounces of water. You can use this while running in between gels. Aim for two per hour of running plus your gels. Price: Bag (40 servings) $27.45
Gnarly Fuel2O: This is a “liquid fuel” to keep life simple. No need to take in gels and sports drinks—and worry about the two messing up your stomach. Fuel2O is a high-calorie, electrolyte-rich, easy-to-digest, drink mix that is designed to keep you going during endurance-focused activities.
Sodium: 250 mg per 12 ounces for one hour of exercise. Take two (500mg with 24 ounces per runs lasting longer than an hour). It also has 25 grams of carbs. No need for gels. Price: 10 sticks: $8.74
Nuun is one of the most popular electrolyte tablets out there. They are clean, gluten-free, and vegan, and come in a gazillion flavors and categories. I’m including information for the Nuun Sport.
Nuun Sport electrolyte tablets: These have just one gram of sugar and a light flavor making it easy to drink—especially when dealing with a sensitive stomach from running long. Sodium: 300 mg per 16 ounces of water. Drop in the tab and let it fizz. Aim to drink close to two per hour of exercise, plus your gels. Price: $7.49 for 10 tabs
Skratch worked with elite athletes to reimagine sports drinks. The result is a simple sports drink with clean ingredients.
Skratch Hydration Drink Mix: This drink mix has 4 grams of sugar per 100 ml, and a replacement of the around the average electrolytes you lose when sweating: 800 mg sodium, 80 mg potassium, 100 mg calcium, and 80 mg of magnesium per liter (about 33 ounces). The flavors are light fruity flavors. Price: $19.95 for 20 servings
Skratch Labs Hyper Hydration: For extreme conditions, Skratch has their passionfruit hyper hydration mix which has a 1,720 mg of sodium! Add contents to 16oz of water. Only drink before extreme exercise, 1 to 2 servings 30 to 60 minutes prior. Mix, drink, sweat (a lot). Price: $2.95 for a single stick.
LMNT was founded according to new science that shows that research touting low sodium as beneficial to our health is wrong—and potentially dangerous. And that when exercising, electrolyte balance is crucial. For that reason, LMNT provides a giant dose of electrolytes per salt stick.
LMNT Recharge: This is your serious salt mix. It packs a whopping 1000 mg of salt and comes in a variety of flavors such as grapefruit salt or chocolate salt. It’s keto, low-carb, paleo, and all-natural. No sugar. No gluten. Drop a stick into 16-24 ounces of water. Mix and sip.
This drink is best for before or after a workout. It’s recommended to take about a half-hour prior to your long run or workout. The site says, “A good thing to remember is when it comes to replacing lost electrolytes–preparing ahead of time is much better than chasing them afterward.”
You can use it to replenish after a heavy-sweaty run such as a long run in the summer heat. Sodium: 1000mg Price: 30 pack for $45.
Solpri Sync Electrolyte Hydration Drink Mix
This company was founded by triathlete Jesse Funk who was on a mission to find natural skin and hydration products for athletes.
Solpri Electrolyte Hydration Drink Mix:
This customizable mix is the only one I know on the market that syncs to your sweat level. You can do an official at-home sweat test that they offer or answer a short survey about how much you sweat and how salty it is, and then they supply you with the best electrolyte-level drink mix.
Solpri’s hydration drink mix is zero sugar with a light, sweet, easy-to-go-down taste “formulated to meet your personal electrolyte needs while supporting your muscles and mind.” It asks: How salty do you feel your sweat is?
Not salty > Choose Low
Somewhat Salty > Choose Moderate
Very Salty > Choose High
Then you choose.
Sodium levels range from 500 to 1500 per serving. Get 60 servings for $39.
Hydration Sample Schedule for Running
There are a thousand ways to skin the hydration cat (sorry for the poor metaphor). Below is an example of how to hydrate for summer running or racing.
- Pre-run: 30 minutes before an intense long run of more than 2 hours in the summer heat, drink an LMNT.
- During the run: Aim to drink one Skratch lab bottle over two hours. Make sure your gel doesn’t include a lot of sodium too. Or drink one to two Gnarly Fuel2O packs per hour.
- Post-run: Rehydrate with your choice of electrolyte drink to recover the weight lost while running.
- Alternate plan: You can also consider taking salt tabs with gels and water as part of your fueling. This option is for people who don’t want to mess with bottles and mixing drinks. Rather, they would aim to use water stops. Still shoot for about 400 mg of salt an hour.
If you want guidance with your training while running pregnant or postpartum, check out my run coaching services. Also, be sure to check out my free training plans: