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How to Perfect Electrolyte Loading Before a Marathon

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In 2018, 1.1 million people participated in marathons, globally. While a worthy goal, the marathon distance is no longer perceived to be limited to elite athletes. With that many runners of all experience levels lining up at the start line, it can be mind boggling to comprehend how different the training strategies can be, even including something seemingly as small as electrolyte loading before a marathon.

With a solid mileage base, training for a marathon can take 16 to 20 weeks depending on the plan. Plans can be found for free online, although many athletes will join a group-training team or even hire a certified running coach to help them prepare for their first 26.2.

The difference here, aside from price, is that the free plans generally don’t include guidance on proper fueling and hydration, whereas those groups and one-on-one athletes might benefit from their coach’s guidance and expertise.

Bottom line, even with guidance, nailing the hydration strategy comes down to some trial and error. Testing different drinks during training helps athletes show up on race day confident in their hydration strategy. When race day is around the corner, what else can athletes do to be prepared, and increase the opportunity for optimal performance out on the course?

text: electrolyte loading before a marathon with a picture of a sprinter

What Is Electrolyte Loading Before a Marathon?

Electrolyte loading is similar to “carb loading,” when a runner increases their carbohydrate intake one to two days in advance of race day to ensure the body is sufficiently fueled. That same concept can be applied to electrolytes, ensuring that the body is sufficiently hydrated heading into a race.

Those heading into their first 26.2 may be wondering about electrolyte loading before a marathon. It’s something many runners do and even talk about. But what is it, and why do they do it? What are they drinking to electrolyte load?

Choosing the right electrolytes can make a difference. There are many options to choose from, and ultimately it comes down to personal preference. For convenience, products such as Gatorade, Powerade, BODYARMOR, and other widely available sports drinks are an excellent option.

Those athletes looking for a zero-sugar alternative might turn to LMNT, Nuun, Tailwind, or other endurance-specific hydration options. Testing different options during training will help an athlete determine what works well for both their hydration levels and their stomach (and what doesn’t).

Should I Drink Electrolytes Before a Marathon?

Generally, yes, athletes should drink electrolytes before a marathon. Although, maintaining the right balance is key. Athletes toeing the line on race day don’t want to show up under- or dehydrated, but they also don’t want to show up overhydrated.

Electrolyte loading is more helpful for athletes tackling longer distances. However, it can also be helpful for athletes expecting to push harder in shorter distances, or running a race on a very hot day. This is important because electrolytes are depleted through sweat. Getting ahead of that depletion will help the body stay hydrated for the duration of the workout.

It’s important to note that a significant increase in drinking plain water prior to a race could throw electrolytes out of balance. When too much water is consumed, sodium levels can plummet because the kidneys can’t get rid of the excess water. This is called hyponatremia, and it can be dangerous. This is why drinking electrolytes before a marathon is generally a better strategy.

Is Drinking Electrolytes During a Marathon Important?

Drinking electrolytes during a marathon is very important. Electrolytes help the body stay hydrated by balancing the amount of water in the body, among other key functions. Marathoners lose hydration and electrolytes through sweat. It’s essential to replace those electrolytes so the body can perform optimally.

It’s ideal to drink more than just water out on the course, whether that means relying on the sports drinks available at the event’s aid stations, or carrying tried-and-true hydration tested during training. Many endurance events will share who their hydration sponsor is on their website. If not, ask which brand will be offered on course.

Most athletes rely on both water and electrolytes, and will either carry both in a mix of bottles or bladders in a hydration belt or vest, carry their own electrolytes and use course-provided water, or will go ultra-light and rely 100% on course-provided aid.


Electrolyte loading before a marathon is a smart strategy to ensure the body is hydrated heading into race day. Testing different sports drinks in advance of race day helps athletes figure out which products work well versus those that don’t.

However, hydration doesn’t end when the race begins. Drinking electrolytes during a marathon is just as, if not more, important to stay hydrated and perform well during the race and recover quickly afterward.

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About the author

Emily is an avid runner who has tackled distances from 5k to marathons. She volunteers at races whenever possible, and loves to encourage newbies to explore running.

Since 2018, she has maintained her RRCA Level I Certified Running Coach credential to be a more informed member of the running community when participating in conversations about training. In short, she really likes all things running.

Read more about Emily here.