• Fenella raced at Challenge Roth for the third year in succession, having finished 3rd and 2nd at her previous attempts
• After leading out of the water, Fenella set off on the 180km bike course alongside five-time IRONMAN World Champion Daniella Ryf. Ryf is renowned for her bike pedigree, and Fenella quickly realised her bike legs weren’t as she’d hoped after suffering with illness during the few weeks prior to the race. This meant that she rode the majority of the course solo, but still managed to keep her spirits high with the help of the infamous crowds lining the course in Roth
• Fenella closed out the race with her first sub-three hour marathon in Roth, coming home in 4th place against one of the highest quality fields in 2023, on a day where World Records were broken in both the men’s and women’s races

Hydration

• Before the race, Fenella drank plenty of water (~1.5L / 48oz) to try and start the race hydrated. In this water, she mixed two PH 1500 Tablets, but for future races we’d recommend reducing the quantity of water these tablets are mixed in, to increase the relative sodium concentration to 1,500mg per litre (mg/32oz)
• This concentration has been shown to optimally increase blood plasma volume and increase the body’s ability to thermoregulate, both of which are important when preparing to undergo some serious sweating
• Fenella’s hydration strategy has changed somewhat in the past few months, moving from primarily pre-mixed electrolyte drinks like at Roth 2021 and Roth 2022, to a more water-based strategy with Electrolyte Capsules to maintain her sodium balance
• This time round, Fenella drank ~2.25L (~79oz) of plain water, and swallowed 15 Electrolyte Capsules. She still kept one 750ml (24oz) bottle with a PH 1500 packet in, meaning her total bike fluid intake had a relative sodium concentration of ~1,500mg/L (mg/32oz)
• Fenella loses 1,331mg of sodium in each litre (32oz) of her sweat, which puts her firmly in the “salty sweater” camp. With temperatures high in Roth on race day (~25℃ / 77℉), and her sweat losses likely high, this combined sodium and fluid intake (~641ml / 21oz per hour) on the bike will have ensured she replaced a good proportion of her losses
• During the run, Challenge Roth has a rule unlike other long-distance races, whereby athletes can pick up their own supply of fuel and hydration from their support crew shortly after every aid station. This eliminates the need to carry gels and bottles for long periods
• Fenella’s partner and coach, Billy, handed her three Soft Flasks filled with PH 1500 at regular intervals throughout the marathon. She managed to drink around three-quarters of each of these, and also picked up ~750ml (24oz) of plain water
• To top up her electrolyte intake whilst drinking the plain water on the run, Fenella also took four Electrolyte Capsules, to bring her relative sodium concentration up to ~1,433mg/L (mg/32oz)
• Fenella’s higher fluid and electrolyte intakes are vastly different to what she hit during the bike and run last year at Challenge Roth. In 2022, where temperatures were marginally higher (~28°C / 82°F), Fenella aimed to drink much more on the run to account for her greater sweat losses, this reduced the sodium concentration to just ~790mg/L
• The more stable intake this year will have helped her body continually process similar concentration drinks to what she was sweating out, making the transition back into her bloodstream more efficient and reducing the likelihood of high/low blood sodium levels

Fueling

Conclusions

• Fenella produced another good performance at Challenge Roth, and the commentators once again drew attention to her relentless happiness throughout and genuine joy to be racing the iconic course
• Her superbly executed fuel and hydration strategy in a hot race, against a stacked field should give her confidence as part of her build towards the IRONMAN World Championships in Hawaii