Sub-4 hour marathon supplementation: a complete and practical guide

The ultimate guide to supplementation for a sub-4-hour marathon, with a practical nutritional strategy based on the products of Crown Sport Nutrition.

How to supplement for a sub-4-hour marathon: the complete strategy with Crown Sport Nutrition

Running a marathon in under four hours is a demanding goal that involves months of physical preparation, well-structured training and, above all, a nutritional strategy that sustains performance from start to finish.

One of the most common mistakes among amateur runners is neglecting nutrition and hydration during the race, which often leads to the well-known "30-kilometer wall".

In this guide we review a clear, practical and scientifically evidence-backed strategy developed by Ruben Cuenca Arce, nutritionist specializing in endurance sports and collaborator of Crown Sport Nutrition, first Spanish company certified against doping by Informed Sport.

Why supplementation is key in a 4-hour marathon

Throughout the 42 kilometers, the body uses its reserves of muscle glycogen as the main source of energy. When these are depleted, the runner experiences sudden fatigue, loss of rhythm, dizziness, concentration problems, and even cramps.

Objectives of a good nutritional strategy

• Maintain stable energy levels with a constant supply of carbohydrates.
• Replenish electrolytes and minimize dehydration.
• Avoid gastrointestinal discomfort, especially in runners not used to ingesting gels or concentrated drinks.
• Train digestive tolerance during long runs.

Pre-phase: strategic hydration in the days prior

The 48 hours before the test are crucial. The idea isn't to "drink more," but hydrate wiselyensuring that the body reaches the starting line with an adequate balance of salts and fluids.

Crown Sport Nutrition Recommendation

1 liter per day of hypotonic drink Isodrink & Energy, dissolving one sachet in one liter of water.

Benefits

• Optimize water reserves.
• Increase the availability of electrolytes.
• Reduce the risk of cramps.
• Arrive at the race with adequate basal hydration.

Nutritional strategy during a sub-4 hour marathon

The goal is to ingest between 50 and 60 g of carbohydrates per houradjusting quantities according to tolerance, perspiration and temperature.

Just before departure (15–20 minutes)

• 1 Energy Gum Bar: rapid activation and immediate glucose supply.

Hydration during the race

Recommended mix:

• 3 scoops of Isodrink & Energy in 500 ml of water (≈80 g carbohydrates/L).

Rate of intake

• Drink 500 ml every 2 hours.
• At aid stations, drink according to how you feel: 500–1000ml.
• Prioritize water when taking gels.

All Crown products include sodium, which is essential for promoting hydration and improving carbohydrate absorption.

Carbohydrate intake: a guide by time and kilometer

Use of caffeine (optional)

• Energy Gel + Caffeine
• HyperGel 45 + Caffeine

Benefits

• Higher concentration.
• Reduced perception of effort.
• It helps maintain the pace in the final stage.

How to train with supplementation

• Use the same products in long runs.
• Try smaller quantities at first.
• Adjust if discomfort occurs.
• Test caffeine tolerance in real fatigue situations.

Conclusion: Nutrition as a weapon to achieve sub-4 hours

Breaking the four-hour mark isn't just about physical preparation. A structured nutritional strategy helps prevent energy crashes, maintain pace, and reach the finish line successfully.

Combining Isodrink & Energy, Energy Gel, Energy Gum Bar y Hyper Gel 45 It offers a complete solution for runners seeking energy stability and good digestibility.

About Crown Sport Nutrition

Crown Sport Nutrition is a benchmark in high-performance nutrition in Spain, with Informed Sport certification, 15 Q1/Q2 scientific publications and collaboration with institutions such as UCAM or the University of Greenwich.

Among their athletes, the following stand out: Carlos Alcaraz, David cantero, Marta Sanchez y TeamNL, among many others.