Laura Siddall
IRONMAN® World Championships
Laura's headline numbers
Laura'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.
Laura is an experienced triathlete with five IRONMAN World Championships under her belt and she used a similar fueling strategy to last year to ensure she finished the bike leg feeling strong en route to securing her first sub-nine hour finish in Hawaii. However, throughout the run she felt a few more energy dips. This may have been a result of her carbohydrate intake dropping lower than she’d planned, ~16g/h less than her last World Champs. Therefore we’d recommend she looks to maintain her carb intake over the marathon.
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 Laura’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 moreAs would be expected in the heat and humidity of Kona, Laura successfully met her fluid targets by taking in a high intake of over ~1.1L per hour on the bike and continued this on the run by drinking over ~1L/h. Alongside this fluid, Laura had PH 1500 (Tablets) mixed in some of her bottles on the bike and a few Electrolyte Capsules on the run, but didn’t take in as much as she had planned. Considering the heat and therefore her high net sodium losses over the nine-hour race, she could have increased her sodium intake to give her full confidence that she would avoid any potential negative performance consequences that can occur if the deficit becomes too much.
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.
Laura had an extremely high caffeine intake over the course of the race, sitting at 19mg/kg (over three times the recommended guidelines). While Laura is someone who has a high tolerance of caffeine and didn’t mention any negative effects from this high caffeine intake, if she decided to aim to hit the top end of the general recommended guidelines instead, she could simply swap out a few more of her caffeine gels for regular gels. As the science suggests that there is no additional ergogenic benefit to taking in more than 6mg/kg, whilst it would also reduce the chances of negative side effects that could occur (e.g. jitters and sleep disturbance).
How Laura hit her numbers
Here's everything that Laura ate and drank on the day...
Laura's weapons of choice
Final thoughts
Laura
PF&HLaura's full stats
Data Confidence?
There is some confidence in the quantities and brands of products consumed but the data may lack specifics (e.g. volumes specific flavours). A high number of estimations have been made and the room for error is moderate-high. There may also be the possibility that some intake has been grossly over- or under-estimated.