U.S. Marathon Hydration Strategy: Tips from ACSM & Fixx Nutrition

As runners around the world prepare for the 2025 marathon season, training plans are well underway for some of the biggest races on the calendar. 

The US hosts some of the most iconic marathons, drawing elite athletes and passionate weekend warriors alike. Whether it’s the historic Boston Marathon, the scenic Chicago Marathon, or the electrifying atmosphere of the New York City Marathon, these races demand not just physical endurance but also a solid preparation strategy.

Hydration and nutrition are key components to the success of any marathon. Without a proper plan, runners risk dehydration, cramps, and possibly being sidelined. If you were to ask The American College of Sports Medicine (ACSM) what they believe is one of the key reasons athletes don’t perform at their best on race day, the answer would be improper nutrition and hydration.

Fluid intake, electrolyte balance, and carbohydrates are all vital if a runner is looking to maximise their potential and capitalise on all the training that they’ve done.

At Fixx Nutrition, we’ve spent a great deal of time working with performance coaches and professional sports organisations to better understand the ways in which athletes, particularly runners, can improve.

We also have a deep understanding of hydration needs and over the years we’ve received plenty of emails with the subject, ‘How to hydrate for marathon’. So, in today’s blog, we shine the light on everything you need to know. We also include a few key hydration tips from ACSM.

If one of the many U.S. marathons is on your list this year, then this post is just for you.

List of Key 2025 U.S. Marathons

To start, let’s take a look at some of the key U.S. marathons scheduled for 2025.

• LA Marathon – March 16, 2025 | Los Angeles, CA
  • Follows the “Stadium to the Stars” course from Dodger Stadium to Century City, passing iconic Hollywood and Beverly Hills.
• Boston Marathon – April 21, 2025 | Boston, MA
  • One of the most prestigious marathons in the world, known for its challenging hills and qualification requirements.
• Big Sur International Marathon – April 27, 2025 | Big Sur, CA
  • A scenic but tough marathon with stunning coastal views along the Pacific Ocean.
• Chicago Marathon – October 12, 2025 | Chicago, IL
  • Known for its flat course, making it one of the best races for setting PRs.
• Marine Corps Marathon – October 26, 2025 | Arlington, VA
  • One of the largest marathons in the U.S., offering a historic and patriotic route.
• New York City Marathon – November 2, 2025 | New York City, NY
  • The largest marathon in the world, taking runners through all five boroughs of NYC.

Why Hydration Matters for Runners

ACSM has guided tens of thousands of runners over the years as they look to improve their running performance. A particular area of focus for the organisation is hydration. Here’s what they have to say.

Proper hydration is far more important than most endurance athletes may think. Running a marathon very quickly depletes fluids, especially in warmer conditions or during races that are longer than usual for the athlete. Here’s why hydration is critical:

• Regulates Body Temperature – Staying hydrated helps prevent overheating, which can lead to exhaustion and heat stroke.
• Maintains Blood Volume – Dehydration reduces blood volume, making it harder for the heart to deliver oxygen to muscles.
• Supports Muscle Function – Water and electrolytes keep muscles working efficiently, reducing the risk of cramps and fatigue.
• Boosts Performance – Even mild dehydration can slow you down and make running feel harder than it should.
• Aids Digestion – Proper hydration helps the body absorb key nutrients that enable athletes to perform at their best.

The fact of the matter is, ignoring hydration can wreck your race, no matter how strong your training has been.

The Impact of Poor Hydration

As we mentioned earlier, many runners underestimate the effects of dehydration. If you don’t hydrate properly before and during a marathon, here’s what can happen:

• Fatigue Sets in Early – A lack of fluids will lead to an early energy crash in your race.
• Increased Heart Rate – Dehydration forces your heart to work harder, making the run feel more intense.
• Muscle Cramps – Low sodium levels due to sweat loss can cause painful muscle cramps, derailing your race.
• Heat Stroke or Exhaustion – Runners lose litres of sweat over a marathon, and without adequate hydration, the risk of heat-related illnesses increases.
• Slower Recovery – Dehydration delays muscle repair, making post-race soreness and stiffness last much longer.

We always recommend that runners follow a structured marathon training hydration plan to help avoid these negative effects.

Staying Hydrated With the Right Supplements

It’s not only about drinking enough water before and during the race. There are other factors to consider, including a combination of electrolytes and carbohydrates. This is where supplements come in, offering a convenient way to take what you need with you.

Look for supplements that include the following:

H3 1. Sodium Intake

• The ACSM recommends 300–600 mg of sodium per hour for endurance athletes.
• Sodium helps maintain fluid balance, prevents cramping, and ensures muscles keep firing.
• Fixx Nutrition’s Fuel X endurance formula is packed with optimal sodium levels to sustain your running performance.

H3 2. Carbohydrate Intake

• Carbs are the body’s main fuel source for endurance running.
• ACSM suggests 30–60g of carbs per hour during long-distance races.
• Fuel X contains complex carbohydrates, which deliver a steady energy supply without causing gut distress.

At Fixx Nutrition, we’ve worked closely with sporting professionals to create a range of natural products that give just the right amount of minerals to help runners perform at their best.

Fixx Nutrition’s Range of Marathon Supplements

Our high-quality range of sporting supplements is designed for long-distance runners who need reliable hydration and energy.

• Fuel X Endurance Fuel – A complete hydration and fuelling solution with electrolytes, carbohydrates, and gut-friendly ingredients.
• CrampFix – A fast-acting cramp relief supplement, perfect for preventing and treating muscle cramps during training and racing.
• Energy gels – Perfect for athletes who choose to aim high and push the limits. These gels are convenient and packed with everything a runner needs.

Due to our scientifically backed and all-natural focus, Fixx Nutrition is trusted by professional athletes and sports teams around the world. If you’re ready to join the list of athletes who turn to Fixx Nutrition to improve their performance, take a look at our high-performance sports supplement range.

If you’re looking for sporting or nutrition tips, check out our blog to find out more.