Nutritional Support for Endurance Athletes: Glucose, Hydration & Electrolytes

When it comes to endurance sports – whether you’re training for a marathon, triathlon, or long ride – success isn’t just about how hard you train. It’s about how well you fuel your body.

Athletes need a smart balance of glucose (carbs), hydration, and electrolytes to keep energy high, avoid cramps, and recover stronger. Here’s how to make your fueling strategy work for you with these nutritional support tips for endurance athletes.

Glucose: Your Body’s Primary Energy Source

Glucose – the sugar your body converts from carbohydrates – is your muscles’ go-to fuel during long workouts. Your body stores glucose as glycogen in your muscles and liver, but those stores are limited. After about 60-90 minutes of steady effort, they start to run low – that’s when fatigue and “hitting the wall” can happen.

The goal: Keep your glucose levels steady throughout your workout.

Before Exercise:

• Eat a carb-rich meal 2-3 hours before training.

• Choose complex carbs like oatmeal, sweet potatoes, figs, dates, raisins rice, fruit, or toast with nut butter.

During Exercise:

• For workouts longer than 90 minutes, aim for 30-60 grams of carbs per hour.

• For ultra-endurance efforts (over 2.5 hours), increase to 60-90 grams per hour.

• Combine glucose + fructose sources (like gels, chews, or fruit) to improve absorption (up to 90g ) and avoid gut distress. Avoid high fiber foods

After Exercise:

• Replenish glycogen stores within 30-60 minutes.

• Use a 3:1 carb-to-protein ratio for recovery – examples include chocolate milk, recovery shakes, or rice with eggs.

Hydration: Stay Ahead of Thirst

Even a small dip in hydration – as little as 2% body weight lost in fluids – can reduce endurance and focus. Hydration is about more than just water; it’s about keeping your body in balance.

Before Exercise

• Drink 16-20 oz (500-600 mL) of water with a pinch of sea salt or an electrolyte drink 2-3 hours before training.

• Sip another 8 oz (250 mL) about 20-30 minutes before starting.

During Exercise

• Aim for 16-28 oz (500-850 mL) of fluid per hour, depending on your sweat rate and the weather.

• In hot or humid conditions, increase your fluid and electrolyte intake – drinking only water can lead to sodium imbalance (hyponatremia).

After Exercise

• Rehydrate with 1.5x the amount of fluid lost during training (weighing yourself before and after helps estimate this).

Electrolytes: The Unsung Heroes

Electrolytes – especially sodium, potassium, magnesium, and chloride – are essential for nerve function, muscle contraction, and maintaining hydration balance.

When you sweat, you don’t just lose water – you lose electrolytes, especially sodium. Without replacing them, you risk muscle cramps, dizziness, or fatigue.

How to Stay Balanced

• Consume 300-800 mg of sodium per hour during endurance exercise. If you are a salty sweater (white marks on arm pits) aim towards the higher intake

• Use electrolyte tablets, powders, coconut water or sports drinks instead of plain water alone.

• After training, eat foods rich in potassium and magnesium (bananas, oranges, leafy greens, nuts) to support recovery.

Final Thoughts on Nutritional Support for Endurance Athletes

Practice your fueling plan during training – not on race day. Stay consistent with carbs and fluids before, during, and after exercise. Replace electrolytes – especially sodium – to avoid cramping and fatigue. Listen to your body: thirst, energy dips, and cramps are early warning signs to adjust your intake.

The Bottom Line

Endurance success requires preparation. With the right mix of glucose, hydration, and electrolytes, you can train longer, recover faster, and perform at your best.

Ready to Personalize Your Fueling Strategy?

At Grace Concierge, we help athletes optimize performance through customized nutrition and hydration plans. Whether you’re gearing up for your next race or building endurance in training, our experts can help you fuel smarter – not harder.

Book your personalized performance consultation today and start training with confidence.