Science-Backed Health Endurance Athletics

The Importance of Hydration and Nutrition
During a Marathon

By TFN Editorial Team
6 Min Read
Verified by Performance Experts

TFN Initiative: TFN has been educating on the critical importance of Hydration and Nutrition for sporting events in the country. TFN believes in science-backed health solutions that deliver a sustainable, long-lasting positive impact on everyone’s health.

We all know that running a marathon is not easy. It requires a lot of planning, preparation, discipline, building stamina, and mental strength.

We have often found that one thing runners frequently overlook is the critical importance of hydration and nutrition. These are two critical factors that can make or break your marathon experience. Proper hydration and nutrition during a marathon are crucial to your performance and health, especially in India where climate conditions vary from region to region and while moving you may notice that water also changes even in the same city, where varying heat and humidity can make things even more challenging. Let’s break down why these elements are so important and how to manage them effectively.

Why Hydration Matters

The average adult body is made up of about 60% water. Let us dive slightly deeper:

Water Distribution Inside the Body

Water is distributed between intracellular fluid (inside cells) and extracellular fluids (outside cells). Specific organs and tissues vary in water content:

Brain 80–85%

Essential for neural function and nutrient transport.

Lungs 75–80%

Maintaining elasticity and efficient gas exchange.

Heart 75–80%

Supporting muscle contraction and nutrient transport.

Liver 70–75%

Crucial for metabolism and detoxification.

Blood ~50%

Facilitating circulation and nutrient delivery.

Muscle & Tissue ~75%

Reflecting its high metabolic activity.

Bones ~31%

Provides structural rigidity and support.

Teeth 8–10%

Dense mineralized tissue.

Skin Hydration: Human skin contains approximately 64% water, with the dermis (thickest layer) holding about 80% of this water and the outer epidermis holding 10–30%, depending on the layer.

During a marathon, we sweat a lot, and this leads to significant water loss. If we don’t replace the lost fluids, our body becomes dehydrated, which can have severe effects on our performance and health, including skin.

How Dehydration Affects Your Body

Muscle Cramps

Lack of water can cause your muscles to cramp up, making it difficult to run. Many runners experience painful muscle cramps in the middle as well as the later stages of a marathon due to dehydration.

Fatigue & Weakness

Dehydration can make you feel tired and weak and can take a toll on your performance. You may struggle to keep up your pace and feel exhausted much sooner than expected.

Dizziness & Confusion

Severe dehydration can lead to dizziness (which may lead to falling down) or confusion, putting your safety at risk on the course.

Overheating

Water helps regulate your body temperature. Without enough hydration, your body may overheat, leading to serious health issues like heat stroke.

How Much Water Should You Drink?

It’s important to strike a balance between drinking enough water and not overhydrating. Drinking too much water can cause a condition called hyponatremia, where the sodium levels in your body drop too low, which can also be dangerous.

Deep Dive into Hyponatremia

Hyponatremia occurs when the sodium concentration in the blood is too low, which can result from either excessive water in the body or insufficient sodium intake or retention.

Sodium is a critical electrolyte that helps regulate water balance, nerve function, muscle contraction, and blood pressure. When sodium levels drop, water moves into cells, causing them to swell, which can be particularly dangerous in the brain.

General Hydration Guidelines:

Before the Marathon (2–3 Hours Prior)
500 ml – 750 ml

Drink gradually to ensure optimal fluid levels before race start.

During the Race (Every 15–20 Mins)
100 ml – 150 ml

Adjust based on sweat rate, weather conditions, and personal hydration needs.

The Role of Nutrition During a Marathon

Nutrition is the fuel that powers your body throughout the race. Without the right fuel, your body will struggle to perform, especially during long races like half or full marathons.

What Happens If You Don’t Eat Enough?

Hitting the Wall

“Hitting the wall” is a term used by marathoners to describe the point when your body runs out of energy, usually after 30–35 km of running. This happens when your body burns through all its glycogen (stored energy) and has no quick source of energy left.

Lack of Focus and Energy

Without proper nutrition, your mental focus and physical energy will decline gradually. You’ll feel quite sluggish and unable to keep up with the demands of the race, let alone complete it.

What to Eat Before, During, and After the Race:

Carbohydrates are your body’s main source of fuel during a marathon. Here’s how you can manage your nutrition:

Before the Race (3–4 Hours Prior)

Carb-Rich Meal for Sustained Energy

Eat a carb-rich meal. Indian foods like poha, idli, upma, or dalia are excellent choices. Avoid especially heavy, oily, or spicy foods as they can cause stomach discomfort.

Poha Idli Upma Dalia
During the Race

Extra Fuel & Electrolytes

For long races, your body will need extra energy during the marathon. Many runners use energy gels, bananas, or sports drinks that contain carbohydrates and electrolytes. Bananas provide quick energy and help prevent muscle cramps due to their potassium content.

Energy Gels Bananas (Potassium) Sports Drinks
After the Race

Carbs + Proteins Recovery

After finishing, focus on refueling with a combination of carbohydrates and proteins. Simple Indian meals like dal-rice, paneer with roti, or vegetables & dal with roti are good options to help your body recover.

Dal-Rice Paneer with Roti Vegetables & Dal

Electrolytes: It Isn’t Just Water, But Salts Too!

When you sweat, you lose more than just water—you also lose electrolytes, including sodium, potassium, and magnesium. Electrolytes are essential for muscle function and keeping your body’s fluids balanced. Without enough electrolytes, you could experience muscle cramps, fatigue, or dizziness.

How to get electrolytes: Drink sports drinks containing electrolytes (especially on hot days) and eat foods like bananas or salted snacks to replenish lost sodium and potassium.

Impact of Poor Hydration and Nutrition

Failing to properly hydrate or eat during a marathon can lead to poor performance or even serious health issues. Some common consequences include:

Decreased Endurance

Without adequate hydration and glycogen, your body tires faster, making it impossible to maintain your target pace.

Risk of Injury

Severe dehydration triggers severe muscle cramping and fatigue, significantly raising injury risks.

Heat Stroke or Exhaustion

In India’s hotter, humid climates, inadequate fluid intake directly leads to serious heat illnesses.

Poor Recovery

Without proper post-race nutrition, recovery slows down, leaving muscle soreness and fatigue for days.

Marathons are doable and will be rewarding, but they require early preparation as they are simply not about just running. If you focus on your hydration and nutrition, you’ll not only feel better during the event but also perform at your best.

Planning for Major Indian Marathons
Delhi Marathon Mumbai Marathon Pune Marathon Indore Marathon Bhopal Marathon

Cross the Finish Line Strong with TFN

TFN brings expertise to guide you in your journey so that you remain focused on outcomes while maintaining optimum levels of performance and health. Stay well-hydrated, energized, and healthy!

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