Fuelling, Hydration & Gut Challenges in Marathon Training
fueling for your marathon
Training for a half marathon or full marathon greatly increases your bodies energy and fluid needs.
Many runners struggle with these three key issues:
Inadequate carbohydrate intake, also known as bonking,
Stomach or GI distress, and fluid or electrolyte imbalance.
For example, 30 to 60% of endurance runners report some type of GI distress symptoms during their races.
Common mistakes reported include, skipping mid-run fuelling, over or under-drinking in the race and, not training the gut in the months before a race to be adapted to the process of fuel digestion.
These problems are more pronounced in full marathon builds due to longer runs and training volumes and doubling the distance means doubling the body’s stress on fuel and fluids.
WHAT IS GOOD RUNNING FORM?
Good form lowers injury risk and makes you more efficient. Stand tall with a slight forward lean from the ankles. Keep your head aligned and look 10–20 m ahead. Swing your arms naturally, elbows about 90°, hands relaxed. Land on your midfoot under your hips; don’t overstride. If you heel strike, increase cadence and aim for a quick, smooth turnover. Brace your core and squeeze your glutes to steady the pelvis. Breathe evenly and relax your shoulders and jaw. Build these habits gradually with regular practice and drills.
HOW TO FUEL A MARATHON
Carbohydrate fuelling is crucial for marathon performance, supplying glucose to working muscles and preserving glycogen.
Begin carbohydrate loading 48–72 hours before race day, increasing intake to about 7–12 g per kg bodyweight while tapering training.
On race morning consume 1–4 g/kg in the 1–4 hours pre-start, favouring easily digestible sources.
During the marathon aim for 30–60 g of carbs per hour; for efforts over 2.5–3 hours target up to 90 g/hour using a mix of glucose and fructose to maximise absorption.
Hydrate appropriately and practise your fuelling plan in training to avoid gastrointestinal issues and ensure optimal performance.