Woman standing in window sill next to a water bottle

Hydration and Fueling for Long Runs

On race day and in training, what you eat and drink is critical to your well-being and success. Your body is working hard, so make sure to give it what it needs! A mindful hydration and fueling plan will help get you through the tough weeks of training and over the finish line.

Why does hydration matter?

Proper hydration is essential to your health and to your performance. Fluids carry nutrients to your cells, cool your body through sweat, and are key to the function of your organs. Dehydration can make you feel lethargic, lead to a decrease in sweat that causes your body to struggle to cool down, or create serious health hazards—especially under physical stress.

How much water do I need to drink?

It varies from person to person, but it’s simple: drink when you’re thirsty. Listen to your body and consider your environment. For example, if it’s a hot day and you’re sweating more than usual, be sure to check in with how your body is feeling and drink more if you need to.

If you know you’re going to be running a long distance, consider drinking about 16 ounces of water beforehand. While you want to avoid dehydration, drinking too much water has its own downsides—so again, listen to your body!

Hydrating before the race

The 12-hour period before the start of your run is crucial to staying hydrated during a marathon. In this period of recovery and preparation, use these hydration tips:

  • Drink 12 to 16 ounces of water before the race.
  • Don’t waterlog yourself right before a race. Drinking too much water can dilute levels of sodium and naturally occurring electrolytes in the blood, causing you to arrive at the starting line depleted of these crucial resources. 
  • One of the easiest ways to monitor your hydration level is to check the colour of your urine (ideally this should be a pale yellow colour).

What about fuel?

While every runner’s nutrition plan will vary, there are some essential guidelines you can follow:

  • Know your vitamins and minerals! Make sure you’re getting enough electrolytes.
  • Fuel up on potassium-rich foods, such as bananas, spinach, and sweet potatoes. Potassium deficiency can lead to severe cramping and poor performance.
  • Choose foods that have a low glycemic index. These foods will cause your blood sugar to rise slowly and give you energy for a longer period of time. Whole grains and oats are examples of a high-fibre source of long-term glycogen.

Centre your snacks and meals around foods that provide these benefits and you’ll see and feel the difference as you’re running.


Staying hydrated and energised during the race

Once you’ve left the starting line and are in the thick of your race, it’s important to have a game plan for staying hydrated and fueled for its (long!) duration. You will get thirsty and your energy might start to wane—here’s how to prepare for, and push through, those moments.

  • Remember to rehydrate. Water stations are there for a reason! Review the course map before race day and take note of where they are. If you are starting to feel thirsty, don’t ignore it—your body is working hard!
  • Embrace the calories. It’s energy! Sugary snacks and sports drinks can give you a quick boost if you’re feeling sluggish. Carry some chewy fruit sweets to eat on-the-go or reach for a sports drink if you need it.
  • Wear your water. A good bottle pouch can go a long way. If you’re going to add an accessory to your race-day wardrobe, make sure you test it first during training for comfort and potential interference with your running. 

You’re ready to race!

Knowing how much water to drink and what foods will you fuel you best before, during, and after your marathon is crucial to running a successful race. Finding the proper balance of hydration and diet may come down to doing what's right for you as an individual. Remember, it is important to drink only when you are thirsty as this is your body’s way of self-calibrating, and eating right involves knowing what gives you sustainable energy, and the foods you are able to tolerate.


Man wearing a red sports jacket.
Woman wearing a red sport zip up.