Ellie Salthouse
Precision Fuel & Hydration IRONMAN 70.3® World Championship
Marbella10th, FPROEllie's headline numbers
Ellie's strategy
Fueling
T - 1-4hrs: Ate a carb rich meal (Low in fat & fibre)
T - 15mins: Took in a final dose of carb
"I didn’t really feel like I was limited by my nutrition intake, I just really struggled to get my legs going on the bike. I’m pleased with a pretty solid run though."
For Marbella, Ellie adjusted her bike fueling plan based on the course profile. The bike course was hillier and slower than a typical 70.3®, so she increased the concentration of PF 30 Gels in her bottles to ensure she could maintain energy intake even as the bike took ~25 minutes longer than normal.
Because energy expenditure is closely related to time on-course, longer bike splits require an increased total carb intake to maintain similar grams of carb per hour. Ellie did just this, and matched her carb intake from her previous races at 70.3®s Melbourne and Zell am See, showing the progression in her fuel strategy.
On the run, Ellie’s carb intake dropped by almost 50% (from ~107g/h on the bike to ~55g/h). This pattern is common among pro and age-group athletes for two reasons: a) logistical limitations - it’s harder to carry and consume nutrition while running, and b) physiological stress - running increases gastrointestinal stress because more blood is diverted to working muscles and less to digestion.
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.
Ellie655mg/L
Ellie has been Sweat Tested to dial in her hydration plan
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 Ellie's losses are on the low 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 moreT - 60mins: Drank ~500ml of strong electrolyte drink
"I felt a bit thirsty when I started the run, but nothing which worsened throughout the race. I’m pretty pleased with this part of my plan."
Ellie isn’t a naturally heavy sweater, and with that low sweat rate, it means that, unlike many athletes racing in warm conditions, she doesn’t need to replace high volumes of fluid or sodium, but still replaces an appropriate percentage of *her individual losses*. Her total fluid intake during the race was one of the lowest we analysed in the professional women's field, yet she limited her body weight loss to ~1% - comfortably within the research-supported range (0-2%) associated with maintaining 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.
T - 0-4hrs: Had a final hit of caffeine
Caffeine has consistently been part of Ellie’s race strategy. She routinely exceeds the scientifically accepted guidelines for the stimulant during endurance sports. While some athletes experience side effects at higher doses (elevated heart rate, jitters, GI distress etc.), Ellie tolerates caffeine extremely well and uses it to push the limits of performance. Ellie's confidence in her tolerance - backed by practising in training - explains why she is willing to sit at the higher end of caffeine intake.
How Ellie hit her numbers
Here's everything that Ellie ate and drank on the day...
Final thoughts
“I think my ‘zap’ was just missing on the bike. I set myself up to get a top 5, but to be dissatisfied with a top 10 at Worlds seems crazy, given how my year started with having surgery.”
“Ellie executed her nutrition plan exceptionally well - maintaining high carb availability, preventing excessive dehydration, and leveraging caffeine effectively. The limiting factor on the day wasn’t fuel or hydration but bike power output relative to the front pack. Her strong run performance highlights that her energy and hydration availability were exactly where they needed to be. With one race left in her 2025 calendar, T100 Qatar, she’s set up to finish the season on a high.”
PF&HEllie's full stats
Data Confidence
We rate each of our case studies from 1-5 based on the level of accuracy, and our confidence in the data.
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.