Atacama Crossing training: 250 kilometres that start at 3,200 metres

The Atacama Crossing is based at San Pedro de Atacama, Chile. It starts at 3,200 metres in the Arcoiris Valley and finishes six stages and 250 kilometres later at 2,400. You climb 2,813 metres and descend 3,646. The ground runs from salt flat to dune to slot canyon, with river crossings. You carry your food and kit; RacingThePlanet provides water, tents and medics. The 2027 edition, the 19th, runs 4 to 10 April.

I start an Atacama plan with altitude, then the cold at night. Heat comes third.

The first stages are run high

Camp 1 sits above 3,000 metres. A runner who arrives from sea level gets less oxygen with every breath for the first days. Effort climbs, easy pace slows, appetite drops and sleep gets worse. Those first days are stages one and two, with a full pack. The runner who holds their home easy pace there is spending the Long March early.

If the calendar allows, I would arrive a few days early. Either way, the first two stages go by effort, not pace, with the heart-rate cap set lower than at home. At altitude heart rate is a rough proxy at best. It rises for the same work, so I trust the athlete's breathing and effort over the number.

Warm afternoons, nights near freezing

The organiser's April figures are highs of 22 to 28°C and lows of 2 to 6°C. A second organiser page gives averages of 22°C and 5°C. A sleeping bag rated to 0°C is mandatory. Older race reports of 46°C come from September editions. The race now runs in late March or April, and I leave those numbers out of an April plan.

Cold camps are a recovery problem. A runner who sits shivering in damp kit after a stage eats less and sleeps worse, and pays for it the next morning. So camp is rehearsed: a warm layer on the minute you stop, a hot meal early, feet dealt with before dark. I test the 0°C bag on a cold night in training, because that bag is also some of the heaviest kit in the pack.

More down than up, with a pack

The course loses 833 metres more than it gains. Descending with nine or ten kilograms on your back loads the quads harder than descending light, and that damage adds up across six stages. I build loaded descents into the spring, progressed in small steps, on top of winter strength work. The descents note covers how. Runners also report the salt crust as hard on the ankles, so I want ankle and calf strength and some rough, uneven ground in the build. River crossings mean wet feet, which means a foot routine practised wet.

The Long March, after four days

Stage 5 is 81 km, with an optional sleep at the overnight checkpoint. Runners who have done the 4 Deserts races say the hard part is starting it after four marathon-length days with no taper. They also report that most of the field fast-hikes. So the backbone of an Atacama build is loaded hiking on consecutive days, and the walking note is the method. I want the athlete to decide before the race whether they will use the sleep, and to have rehearsed that choice on an overnight training walk.

Food matters as much. The minimum is 14,000 kcal, 2,000 a day. One runner reports shop-bought freeze-dried meals turning into salty paste by day three. Test meals on the fourth day of a training block, not the first. The carbs note covers the on-the-move part.

Reading fatigue when altitude moves the numbers

Race-week data at 3,000 metres will not compare with home data, so the durability reads come from the build. Loaded hiking speed at the easy cap on day three of a three-day block, against day one. Loaded descending late in a long day against the same descent fresh. The watch cannot see the pack, so loaded sessions get logged by hand. When the cost rises, the watch shows that it rose, not why. Legs, sleep, food or the pack are all possible. I ask, then I decide what the next block holds.

An April race from a British winter

Plenty of the people asking about this race online are newer runners planning a two-year progression. I think that is sensible. The long run grows by small steps, as in the progression note. The winter is capped easy volume, two strength sessions and loaded walking from early on. Spring brings three-day loaded blocks with descents and one overnight walk. A cold-night kit test comes in March, and a short heat block suits a 28°C ceiling. The taper keeps frequency and drops volume.

What I track for the Atacama

• Loaded hiking speed at the easy cap on day three of a block, against day one.
• Late-day loaded descending against the same descent run fresh.
• How the athlete eats and sleeps on a cold-night kit test in the 0°C bag.
• Which race meals still go down on the fourth consecutive day.
• Ankles and feet after rough, uneven ground and wet sessions.
• Effort and breathing, more than heart rate, on any pre-race altitude trip.

Facts checked October 2026 against racingtheplanet.com: the Chile home, at-a-glance, quick facts, course, itinerary, equipment and rules pages, the organiser's course table and its entry store. Confirmed: 250 km over six stages in seven days, self-supported, stages of 35.3, 37.5, 39.8, 44.4, 81.0 and 12.0 km, 2,813 m of ascent and 3,646 m of descent, a 3,200 m start and 2,400 m finish, checkpoint cut-offs from 4 km/h, 14,000 kcal minimum, 35 mandatory items including a 0°C sleeping bag, pack advice under 10 kg, and fees of US$4,200 and $4,500. The organiser's pages disagree on the late-fee date, the field cap (100 or up to 200), the temperature ranges and the fastest time; both temperature figures are given above. Editions up to 2023 ran in late September (secondary); 2025 ran in late March, 2027 runs in April, and the organiser's news lists no 2026 edition. The organiser publishes no overall time limit or finish rate; 127 finishers in 2025 is secondary. Runner experiences are reports, not facts. Evidence level: altitude, load carriage and eccentric loading match the field notes; camp routine is coaching practice.