Lizzie Rayner
Precision Fuel & Hydration IRONMAN 70.3® World Championship
Lizzie's headline numbers
Lizzie's strategy
Fueling
Carbohydrate is the main fuel you burn when racing. Failing to fuel properly is a leading cause of underperformance in longer races.
Despite nailing her carb load in the days leading into the race and her breakfast on race morning, Lizzie felt flat on the bike. Reflecting on her pre- and in-race fueling, this feeling was likely from the notoriously challenging bike course with over 1700m of elevation. She did well to stick to her plan of consuming over 130g of carb per hour thanks to her new and improved strategy of PF 300 Flow Gel, PF 30 Gels and PF 30 Caffeine Gels. She had practised this in Portugal just three weeks earlier and it set her up effectively for a PB run performance (1:19:46). Overall, she averaged a career-high ~110g/h, a significant step up from the ~78g/h she averaged at races in 2024. This increase in carb intake surely played a key role in helping her reach her goal of a top 10 finish at the World Champs.
Hydration
Taking on board an appropriate amount of fluid and sodium is essential to maintaining blood volume and supporting the cardiovascular effort needed to perform on race day.
Whilst the absolute amount of sodium and fluid consumed per hour is important, it’s critical to consider these in relation to each other. This is known as 'relative sodium concentration' and it’s expressed in milligrams per litre (mg/L). How much sodium you’re taking in per litre of fluid is more important than the absolute amount taken in per hour.
Sweat sodium concentration (mg/L) is largely genetically determined and remains relatively stable. Knowing how salty your sweat is enables you to replace a good proportion of your sweat losses, which can range from 200-2,000mg/L.
Whilst Lizzie’s losses are on the moderate side, getting her hydration strategy right is still crucial when it’s hot and/or humid as her higher sweat rate in these conditions can result in significant net losses over the duration of a race.
Learn moreAfter some cramping in recent races, Lizzie wanted to ensure her hydration strategy was proactive enough to mitigate against cramping whilst also considering the weight impact of carrying more bottles on such a hilly bike course. She struck this balance well, carrying two bottles to start the bike before picking up PH 1000 (Tablets) on course, then switching to bottles and cups of both PH 1000(Tablets) and water on the run. This helped her drink ~37% more per hour than in Portugal, where she averaged only ~522ml/h. Using a combination of PH 1500 (Tablets) and PH 1000 (Tablets), she maintained an appropriate fluid and electrolyte balance, consuming sodium through fluids at a rate similar to her sweat sodium losses. This well-considered intake was backed up by pre-/post-race bodyweight measurements that demonstrated a textbook ~2% bodyweight change; a level shown to be just within the acceptable dehydration threshold for performance.
Caffeine
Beyond the Three Levers of Performance (carb, sodium and fluid), caffeine is one of only a few substances that is proven to improve performance for most endurance athletes as it can help stave off mental and physical fatigue.
One PF 30 Caffeine Gel before the swim and two on the bike put her well within the recommended caffeine range to enhance focus, perceived energy and endurance performance.
How Lizzie hit her numbers
Here's everything that Lizzie ate and drank on the day...
Lizzie's weapons of choice
Final thoughts
Lizzie
PF&HLizzie's full stats
Data Confidence?
There is good confidence in the accuracy of the data reported. An athlete feels that the numbers closely reflect what they consumed despite a couple of estimations which may carry some degree of error. The majority of what was consumed is recorded to a high level of specificity (most volumes are known through the use of bottles brands quantities flavours). The numbers are very plausible and align with previous data recordings (if an athlete has collected data previously).