Completing a desert ultra-marathon is no small feat – as these two UK endurance champions reveal

WORDS: Rob Kemp

The extreme heat, harsh terrain, and mental challenges make desert ultramarathon races among the toughest endurance events in the world. The Desert Ultra in Namibia, this November part of Beyond the Ultimate’s Global Race Series, brought 40 competitors face-to-face with gruelling conditions. Leading the field from the UK were Harry Edmonds, 24, from Guildford running his first desert ultra and Jon Shield, 41, from Shropshire, aiming for his fifth BTU race win.

The challenge: Namibia’s desert ultra

The Desert Ultra spans 250Km across Namibia’s arid landscapes, from the Spitzkoppe Mountains to the Save the Rhino Outpost. Over five days, runners face:

  • Temperatures reaching up to 55°C during the day and dropping to 5°C at night.
  • Terrain that includes sand dunes, rocky passes, and volcanic craters.
  • Wildlife – unlike the Marathon des Sable the Namib desert is home to desert-adapted lions and wild elephants
  • Self-sufficiency – runners to carry their food and gear while managing hydration and nutrition.

For many, the race’s final 90km stage is the ultimate test of endurance, pushing participants to their physical and mental limits. Shield secured victory across all five stages, completing the course in an impressive total time of 27 hours and 39 minutes. He described it as a relentless battle with the environment. “There’s no shade in the Namib Desert. It’s an unforgiving place. The heat and terrain don’t let up.”

Heat acclimatization

Both Shield and Harry Edmonds emphasized the importance of training for the extreme heat.

“Your body needs to acclimate to perform efficiently and avoid heat-related issues,” Shield explained. Using a heat chamber in London, he replicated desert conditions, running for an hour at temperatures up to 48°C.

Harry also incorporated heat chamber training and sauna sessions. “At first, I could barely last 20 minutes in the heat chamber,” he said. “But over time, I built resilience and learned how to manage my core temperature.”

Endurance and strength training

The Desert Ultra’s distance demands a strong endurance base, but strength and injury prevention are equally critical.

“You can’t just clock miles,” Harry said. “I focused on core strength and mobility, which helped me handle the physical toll of five consecutive days of running.”

Along with his regular training, Jon Shield even had to run 18 ½ miles to a train station with a full pack after a 12-hour shift as a paramedic, to get to London for two heat chamber sessions in a day. “That was tough and out of the ordinary but if you don’t do the heat acclimatisation you won’t last the course,” says Shield. “Experience counts for a lot too. Through the events I’ve done I’ve learned how to pack efficiently, prep meals quickly, and minimize my pack weight. These small things save time and energy.”

In-race strategies

Pacing – Overexertion in extreme heat can be disastrous. Harry slowed his pace and focused on deep, steady breathing to manage his effort. “You can’t fight the desert. You have to adapt to it,” says Edmonds. “Early morning starts are key to avoiding the worst of the heat.”

Nutrition and hydration – In the desert, staying fuelled and hydrated is critical. “I tested my salt intake and hydration needs in training,” Edmonds explained. “In the heat, salty snacks like biltong worked better than sweet gels.”

Jon Shield, agrees. “I rely more on fluids for nutrition in hot environments. It’s about knowing what your body can handle.”

Mental Resilience – Breaking the race into smaller goals was essential for both runners. “Thinking about the full 90km stage is overwhelming,” Harry said. “I focused on running to the next checkpoint.”

For Shield, mindset was equally crucial. “Eat, drink, sleep, run—repeat. Everything becomes simple, and I thrive in that clarity.”

Challenges on the course

The Namibian desert offers no shade and is home to wildlife, including desert-adapted lions and elephants. Runners must be prepared for the unexpected. “You’re at the mercy of the environment,” Shield said. “It’s not just about running – it’s about adapting.”

Last year, Shield was forced to withdraw from the Desert Ultra after contracting a stomach bug. “Traveling to these countries can bring health risks,” he said. “Sometimes, you just have to accept it and move on.”

What’s next?

For Harry Edmonds, the Desert Ultra is part of a larger journey in the Beyond the Ultimate’s Global Race Series, which spans the world’s toughest environments.

Harry finished 7th overall and 5th male with a total time of 41:25:00, cementing his place as one of the series’ youngest achievers. For him, the finish wasn’t just about placement but about proving what’s possible. Next up is the BTU Ice Ultra, a 5-stage 230km race. “I’m swapping sand for snow,” says Edmonds. “It’s going to be a whole new challenge, but I’m ready for it.”

Shield, having completed the Global Race Series with victories in every stage, isn’t slowing down either. He plans to tackle the 472-km mile Arctic Spine (www.thespinerace.com/race/arctic/arctic-spine/) race dragging a pulk.

“There’s always a harder challenge,” he said. “I approach these races differently—training harder and smarter, pushing my limits every time.”

For more information on the Desert Ultra and Beyond the Ultimate’s Global Race Series, visit Beyond the Ultimate.