How to use the fuelling planner
- Pick your race. The list includes Spanish half marathons whose aid station positions we have checked. For any other race, choose Other race and the plan assumes an aid station every 5 km, which is the usual layout in Spain.
- Enter your goal time.
- Set your gel strategy: how often you take a gel, when you take the first one and how many grams of carbohydrate each gel has (check the label, most have 20–30 g).
The plan lists every aid station and gel in order, with the race time and, when the start time is known, the time of day. If a gel falls within 5 minutes of an aid station, it moves to that station so you can take it with water.
How much should you take in a half marathon?
- Under about 1 h 15 min: most runners need little or no fuel during the race. A good breakfast and water are enough.
- 1 h 15 min to 2 h: 1–2 gels, or about 30–60 g of carbohydrate per hour, helps you hold pace in the last 5 km.
- Over 2 h: 2–3 gels spread evenly, starting around 40 minutes in, keeps energy steady.
Never try a new gel on race day. Practise your exact plan on two or three long runs first.
Drinking at Spanish aid stations
Aid stations (avituallamientos) usually offer water in small bottles or cups, and from around km 10–15 some races add isotonic drinks and fruit. On hot days:
- Drink small sips at every station rather than a lot at once.
- Take a gel with water, not with a sports drink, to avoid a sugar overload.
- In spring and autumn races in the south, use water to cool your head and neck too.
Frequently asked questions
Where do the aid station positions come from? From the official race regulations or course maps. They can change between editions, so check the latest course information before race day.
Why no gel in the last 10 minutes? It takes around 10–15 minutes before a gel helps, so a gel that close to the finish only adds stomach risk.
Want the pace for each section? Use the pace calculator for kilometre splits, and the time limit checker to make sure your goal fits the race.