Running long distances is as much about strategy as fitness. The body’s stored energy can only carry you so far — after 90–120 minutes, glycogen (stored carbs) starts running low. Without proper fueling, fatigue and “the wall” set in. With the right plan, though, you can keep running strong all the way to the finish.

The Science of Energy in Long Runs

Glycogen Storage: Muscles and liver hold ~90–120 minutes worth of running fuel.

Blood Glucose: Mid-run carbs prevent sharp drops in blood sugar.

Fat Utilization: As glycogen depletes, fat provides backup energy, but it’s slower to convert — hence the slowdown without fueling.

Goal of fueling: Replenish glycogen + maintain blood glucose = sustained pace and endurance.

How Much to Fuel

General Guideline:

  • 30–60 g carbs per hour for runs >90 minutes.
  • Up to 90 g/hour for marathons/ultras if using a glucose + fructose blend.
  • Hydration: 400–800 ml fluid per hour, adjusted for sweat rate and conditions.
  • Electrolytes: Sodium, potassium, and magnesium to replace sweat losses and prevent cramps.

What to Fuel With

Carbohydrate Sources

Energy Gels: Fast, portable, and easy to absorb.

Sports Drinks: Combine fluids, carbs, and electrolytes.

Chews/Bars: Slightly slower release, add variety.

Natural Options: Bananas, dates, honey, or boiled potatoes (popular in ultras).

Electrolytes

Tablets, powders, or drinks with sodium + potassium.

Aim for 300–600 mg sodium per hour in hot conditions.

Caffeine (Optional)

Boosts alertness and reduces perceived effort.

Use 30–60 mg every 1–2 hours if tolerated.

Timing Your Fuel

Start early: Don’t wait until you feel tired — begin fueling ~30–45 minutes into the run.

Small, steady intake: Every 30–40 minutes is better than large gaps.

Practice in training: Teaches your digestive system to handle carbs while running (“gut training”).

Pre- and Post-Run Fueling

Before: Carb-rich meal 2–3 hours before; snack (banana, toast, rice cake) 30–60 minutes before.

After: Within 30–60 minutes, eat carbs + protein (3:1 ratio) plus fluids to restore glycogen and repair muscles.

Common Mistakes to Avoid

Under-fueling: Waiting too long or not taking enough carbs leads to glycogen crash.

Over-fueling: Too many carbs at once can cause stomach issues.

Only drinking water: Leads to electrolyte dilution (hyponatremia).

Trying something new on race day: Always test gels, drinks, and foods in training first.

Long-distance fueling is a planned strategy — not an afterthought.

Before: Fill glycogen stores with carb-rich meals.

During: 30–60 g carbs + fluids + electrolytes per hour.

After: Replenish and repair with carbs + protein.

Fuel smart, and your body will have the energy to carry you not just to the finish — but through it, strong.