IM Western Australia
Fenella's headline numbers
Carbohydrate is the main fuel you burn when racing. Failing to fuel properly is a leading cause of underperformance in longer races.
Fenella executed her pre-race fuel plan perfectly and left nothing to chance. She carried all of her carbs from start to finish, frontloading her intake like she usually does using bottles of plain water and Flow Gel. After this she dropped her carb consumption by ~26% during the marathon, which was still enough to sustain her effort. Fenella’s average intake was very similar to her strategy at the 2023 Challenge Roth, where she finished within four minutes of her overall time here in Western Australia, so it’s clearly working well for her.
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.
Given Fenella’s losses are High (1,331mg/L), nailing her hydration strategy becomes especially crucial when it’s hot and/or humid.Learn more
As you can see from the graphic above, Fenella loses a high amount of sodium in her sweat, so replacing this requires some proactivity. She did this by drinking just under 1L of water from her bottles on the bike, and taking between 3-4 Electrolyte Capsules alongside. This meant that the relative sodium concentration of her intake was impressively close to her sweat sodium losses (1,316mg/L vs 1,331mg/L), so will have replaced a high proportion of what she lost through sweating. Being able to pick up two Soft Flasks of PH 1500 made this electrolyte replacement during the run much easier than normal, and is something Fenella’s implemented successfully several times before.
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.
Once again, Fenella crushed her caffeine intake at all points of race-day, to reap maximum benefit from the stimulant. She’s a frequent coffee drinker, and suffers no ill effects from higher-than-average doses of caffeine, so hitting just over the general guidelines is likely appropriate for her and we wouldn’t recommend changing anything at this point.
How Fenella hit her numbers
Here's everything that Fenella ate and drank on the day...
Fenella's weapons of choice
Fenella's full stats
There is an adequate level of accuracy in the data collected and the numbers reported. The athlete manages to recall what they ate and drank including most specifics (brands flavours quantities plausible estimations of volumes). However there are estimations made within the data which affect the overall confidence level in the data reported.