The Half in the Walled City: Surviving the Cartagena Furnace

Two laps and a real 298 meters

21.1 km over two laps in and around the walled city, with a passage over the walls. The official page labels it as flat, but lists 298 m of elevation gain: it's not a wall, but it's not a track either. Add plenty of turns in the old town: in 2016 even some pros took a wrong turn, according to race reports. Study the key points of the two laps before race day and follow the signage carefully, especially when you're cooked on the second lap.

The heat decides the race

The numbers: highs around 31 °C, humidity over 80%. In 2016 the heat index approached 43 °C. Reports from the first edition say non-acclimatized athletes couldn't run continuously and there were DNFs due to dehydration. This isn't a leg where you "grit your teeth": it's a leg where those who did heat acclimatization get through, and those who didn't end up walking. Plan 2-3 weeks of heat exposure before the race (sauna, overdressed workouts, trainer sessions with no fan): it matters more than your last quality block.

The section on the walls

The passage over the walls is the most beautiful spot and the toughest: full sun, zero shade. If you have to pick where to back off, back off there. Better to lose 30 seconds per lap than to blow up at km 15.

Aid stations: what to expect

In 2016 there were about 10 aid stations per lap with water, Gatorade, Pepsi, gels and bananas, plus sponges. Reported weak point: few toilets on the course. Aid station density is good: use them all. Simple protocol at every station: drink, ice down the tri suit if available, water over the head, sponge. Active cooling isn't an extra, it's the plan. Practice it in training: running with a tri suit full of ice is a sensation you want to know beforehand, not on race day.

Pacing and plan B

Our rough estimates (not official data): 2:40 for a relaxed finisher, 2:15 for a mid-range goal, 1:52 for a fast runner, 1:35 for a top age-grouper. Whatever your target on a cool course, start slower here: the first 5 km should feel slow. If the heat bites, switch to a structured run-walk: run between aid stations, walk 20-30 seconds at each one while you drink and cool down. In race reports, it's the strategy that saved the day for many. A run-walk decided in advance always beats an early blow-up.

Do this now

• Lock in 2-3 weeks of heat acclimatization in your build-up plan.
• Practice the ice-water-sponge protocol and the run-walk in training.
• Memorize the two-lap map and the spots where the course turns in the old town.
• Set a conservative starting pace and a clear trigger (heart rate or feel) to switch to plan B.
• Factor in the reported lack of toilets: manage fluids and your stomach accordingly in the days before.