Hydration on Race Day

There are many options when it comes to race day hydration: Should you bring your own handheld or drink what is on course? How often and how much to drink? Should you drink water or electrolyte drinks? Let’s dive into what you need to be thinking about for your race day hydration.

Even before race day, we need to be smart with our hydration, to make sure that we are going into the race well hydrated. This means hydrating the day & night before and the morning of the race.

The night before: Drink 12-16 oz of an electrolyte drink. If your race is over 1.5 hours, and you’ve been carb loading, the extra water you drink with your carb load will help, too.

The morning of: Drink 12-16 oz of an electrolyte drink (or a cup of coffee/tea + electrolyte drink). Stop drinking 1 hour before your race to decrease the need for bathroom stops (sips are ok if needed).

This is a personal decision that only you can make. Think about what will make you more comfortable on race day: not carrying a handheld or bringing your own drink so you know exactly what you are getting.

Pros of carrying your own bottle: not battling at the crowded aid stations, running better tangents without weaving for tables, and drinking the electrolyte drink you trained with each week

Cons of carrying your own bottle: something to hold in your hand, may throw off your natural gait & arm swing without enough practice, and fluid is provided on course

This decision can get tricky, especially if your fluid and electrolyte needs are high. Getting help from a sports dietitian to create a plan that works for your needs is a great option.

If it’s a cool race day and you aren’t a very heavy/salty sweater, it’s possible that drinking water to thirst & with gels or chews can work for you, especially for shorter to half marathon distance.

If it’s warm or you are a heavy/salty sweater, you will need more electrolytes. You can consume electrolytes from one or a combination of: on course electrolyte drinks, electrolyte drink in your handheld, race fuel, and salt caps/tabs.

If you are planning on using an on course hydration drink, practice with it during your long runs, so you know you tolerate it. We don’t want to try anything new on race day!

First, it depends on your individual needs & sweat rate. We need anywhere from 2 – 20 oz of fluid per hour in races over 60 minutes. That’s a wide range. And, we often aim to replace around 1/2 of our sweat losses during a race. We never want to drink back all our sweat losses during a race and we should never drink more than we lose via sweating while racing. <Of note: we never want to drink more than 25 oz fluid per hour as this increases our risk of a dangerous condition called hyponatremia.>

You also need to consider what/where you are drinking. If you are using what’s on course, make sure you look into where the aid stations will be. Many big races and marathons will have them at every mile (or close to it) but others may not.

Most race cups have about 3-4 oz, but how much you ingest will vary. If you stop or slow to a walk to drink, you may be able to drink all or most of it in. If you are running while drinking, it’s likely that you will only get 1-2 oz per cup.

If you are bringing a handheld water bottle, you will know exactly how much you are drinking.

Often, we train in weather that is very different from race day. Ideally, we use the sweat rate calculator to determine how much sweat we lose per hour in predicted race conditions and this can help guide our fluid strategy on race day.

Use your sweat rate data to determine how much fluid you will need, and then figure out how much and how often you need to drink.

We all know that hydration needs are very individualized, and there are many choices to consider with hydration products and drinking methods. The best thing your can do is to have a plan. Use your sweat rate & sweat composition data to make your plan. If you need help, please reach out for a Last Minute Crunch Time Session with Meghann or a Customized Race Day Fuel & Hydration Plan.