In October 2025, I Harry Mackernass took part in the Ultra4Charity Sahara Ultra in Tunisia with Foxy from SAS Who Dares Wins. Getting a call from his team to ask if I wanted to be their veterans ambassador was an odd one, but I got too excited and said yes….
It was marketed as a 100km race, which is technically true in the same way that “you’re in your own time now”. In reality, it came out closer to 110km across two days in the Sahara Desert. Long stages, relentless heat, and very little shade. To make it even harder: there were no crowds, no distractions except the odd camel, just a lot of time to question your life choices while jogging across sand. Thankfully I had an ex-bootneck mate to run it with, and our level of dit-spinning was quite spectacular to be honest.
The training was a challenge in itself. I gave myself a 16-week prep window and had to adapt from hybrid and strength work into long, monotonous endurance sessions. The hardest part wasn’t pain, it was boredom and just being in my own head. I’m not great at that, especially since the PTSD diagnosis. Physically, my hip flexors made their feelings very clear early on; mentally, it felt a lot like familiar military training. Simple task, long duration, no shortcuts, get on with it.
Preparation also meant dropping bodyweight. I lost 17kg over the training block, not as a crash diet but as a deliberate move to make the heat more manageable and the distance more efficient, because dragging 92kg of (essence) muscle mass would have been pointless – Carrying less unnecessary mass in the desert is common sense. You feel it most on day two, when everything is already tired and you’re still expected to keep moving forward. I can say, hand on heart, that the first 5km of day 2 was one of the hardest mental battles I’ve faced in a long time, but there was no way I was stopping. Putting myself in the locker for a couple of days to help others escape it for a lifetime isn’t even an option!
I trained mostly in Thailand, where the heat forces you to respect electrolytes very quickly, and then continued training on the Jurassic Coast once back in the UK. I used the HYDRATE range from Combat Fuel throughout the build-up and during the event itself. Bottles were topped up every 10km without exception at the aid stations – it really helped having some friendly faces and music at those points too because this challenge was tough. There was nothing to see throughout the entire day, which is why it’s so much harder than running through villages or towns like other marathons do. I definitely over stayed my welcome at some of the checkpoints but it got me through each stage so I won’t apologise for that!
Excitingly for me, one of my clients came to run it with me as well – having trained her for a few months to get ready, she smashed it and came 3rd female overall!
As a collective, the event raised £230,000 for four military and veterans’ charities, which was the entire point of being there. The Sahara Ultra wasn’t about proving anything or chasing a finish time. It was about doing something deliberately uncomfortable, staying disciplined when it would have been easier not to, and using that effort to support people who’ve already carried more than their fair share. A long way to run, but a worthwhile reason to do it.
You can see the full video linked here, and I genuinely encourage anyone looking for a new challenge to sign up to the military series – each year it goes to a new location. We’ve done desert, next up is mountains, then snow and jungle to follow… but at least we get to be mates with Foxy!
