Gary Howells has an extensive CV in endurance sports as he's completed the Marathon des Sables, 5x IRONMANS and 15x ultra marathons. The founder of GH Run Coaching is also the owner of a small coffee business.

Naturally, the team at Precision Fuel & Hydration are coffee lovers and keen endurance athletes ourselves so we were keen to find out more about Gary after he became our very first Sweat Test Officer in Wales.

We caught up with Gary just a few days after he'd run 10 marathons in 10 days for charity... 

Morning Gary, you ran an epic 10 marathons in 10 days to help raise money for the Brathay Trust. Firstly, how are the legs feeling and what made you take on this challenge specifically?

Well, I finished the '10 in 10 Challenge' on Sunday 17th May and the legs were actually feeling okay afterwards to be honest, which surprised me!

I developed a quad issue on the ninth day and that's still niggling a bit, but not too bad other than that.

The 10 in 10 has always appealed to me but I could never justify the time off, so lockdown offered an ideal opportunity to finally get it done. I spoke with the Brathay Trust who run the official 10 in 10 and they were so supportive and immediately 100% behind it.

Image Credit: Gary Howells ©

Am I right in saying that you completed all of these marathons indoors?

That's right. Due to lockdown and the restrictions on daily exercise, I decided to do it on the treadmill in what I like to call the “pain cave” - it's a room with fans, tv, surround sound and has everything you need.

So more of a small gym rather than a cave!

Sounds like an ideal set up! How did your fuelling and hydration pan out? Did you find you needed to tweak what you were eating and drinking across the challenge?

I used PH tablets in 2018 when I raced the Marathon des Sables and I've since taken the Sweat Test so I could really dial in the electrolyte strength I need. 

I took a Sweat Test after MdS and that's helped me get a good handle on what I need hydration-wise for my events nowadays.

I was feeling fatigued after about Day 7 of my '10 in 10' so I spoke to JP and he helped me nail my preloading strategy, which changed everything.  

I also used about 40-60g of Vitargo every hour and that's what I used as my source of carbs all the way through.

The 10 in 10 was a great opportunity to gather lots of data and information for my own personal interest and to use it to help other people in the future. It was an epic challenge and a great learning curve.

Gary's '10 in 10' sweat data analysis

Gary lost an average 2.46kg of weight through sweating each day despite drinking on average 1.5L of PH 1000.

The variation in his sweat losses across the 10 days were pretty significant too, with losses varying from 3.3L down to 1.9L.

Gary's been Sweat Tested and loses 901mg of sodium in every litre of sweat.

So, when we looked at both Gary's sweat rate and sweat sodium numbers, it wasn't surprising to see that later on in the challenge Gary started to suffer from a hydration point of view - he was losing ~3200mg of sodium every single marathon!

And we know from experience that it's difficult to handle that volume of sodium depletion during an event alone, which is where the preloading and recovery drinks became even more important.

As an experienced running coach, you've got plenty of knowledge on running biomechanics, so do you think your running gait changes when running on the treadmill? And if so, in what way?

Gait can change in many ways. It will change depending on whether you're walking or running, your speed, your shoe selection and in other ways too. 

Research shows that assessing gait on a treadmill is the best way. If we can get the gait right here then we have a good foundation for moving forward.

As for running form, on the treadmill I believe that changes massively.

When I look at gait analysis in my day job at GH Run Coaching, I don’t just look at foot contact, I also look at the biomechanics of the runner and the effect that has on their running form and gait.

There are many factors to consider, not just what the foot appears to do on initial contact.

Image Credit: Gary Howells ©

And you've recently become a Sweat Test Officer and our first Sweat Test Centre in Wales - tell us a bit about how that came about... 

I recently completed my training and became a Test Centre, which I'm really excited about.

After going back to university to do a degree in Sports and Exercise Science, I started to understand from my lectures that many aspects of performance were leading back to hydration and the importance of it as a building block for everything else we do.

I had done a lot of research in the area and promoted the value of hydration during one of my talks.

The feedback was overwhelming and before I gave any incorrect information out, I started talking to you guys at Precision Fuel & Hydration to help enhance my own understanding. 

Once I knew it was possible to become a Test Centre, I absolutely jumped at the chance.

I've also heard that you have a coffee business and set up shop at events to make sure everyone's suitably caffeinated, are you planning to do the same with Sweat Testing?

Exactly, I've got a small mobile coffee business that goes hand-in-hand with the running and triathlon events. I don’t know many people who run or do triathlon that don’t rely on coffee

I'm in the process of converting a van that will also act as a mobile Test Centre so that I can go to events and offer Sweat Tests.

Brilliant! Thanks for sharing your 10 in 10 experience with us and we're looking forward to working with you as a Sweat Test Centre. 

If you would like to book in for a Sweat Test with Gary, you can contact him on +44 7974 104562 or email