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Laura Siddall

Pro

IRONMAN® World Championships

14th October, 2023
Hawaii
Kailua-Kona
16th, FPRO
Triathlon, Full distance - 226.2km
28°C
, Very Hot
8hrs 59mins
more race details

Laura's headline numbers

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?
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~93
g
Carb per hour
Recommended 90g/h+
~988
ml
Fluid per hour
Recommended 750-1,250ml/h
~323
mg
Sodium per litre
Recommended 400-800mg/L
~19.0
mg
Caffeine per kg
Recommended 3-6mg/kg
Image Credits: @Two26Photography

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.

Carb-loaded
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T - 1-4hrs: Ate a carb rich meal (Low in fat & fibre)
pre-fueled
?
T - 15mins: Took in a final dose of carb
Carb per hour
Recommended 90g/h+
~93
g
Laura's Energy Rating
8
/10
"I didn’t have the extra gear that I would’ve liked but I don’t think that was dependent on my fueling. I felt the stronger in the last 20km of the bike compared to last year as I was able to pass people who were flagging."
Our thoughts

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.

Laura614mg/L
Laura 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 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 more
Pre-loaded electrolytes
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T - 60mins: Drank ~500ml of strong electrolyte drink
Fluid per hour
Recommended 750-1,250ml/h
~988
ml
Sodium per litre
Recommended 400-800mg/L
~323
mg
Laura's Hydration Rating
7
/10
"I was pretty happy with my hydration overall. I could’ve been more aware of how much I was drinking and utilised the Electrolyte Capsules I had with me on the bike and the run as I did last year, but I believe I still managed my sodium needs well."
Our thoughts

As 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.

Pre-caffeinated
?
T - 0-4hrs: Had a final hit of caffeine
Caffeine per kg
Recommended 3-6mg/kg
~19.0
mg
Our thoughts

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's Satisfaction Rating
7
/10
There are always things to improve on and learn from, but after the year and training that I had going into the World Champs, I have to be fairly happy as it was a pretty solid day across the board. I missed the pack on the swim which could have changed things, then compared to everyone else I moved well on the bike and had a pretty solid run to cap it off.
Laura
Laura had a strong race in Kona, feeling happy with her top-20 result and sub-nine hour finish time to end the year. As an experienced triathlete, Laura has developed a well structured fuel and hydration plan over the years. To avoid any performance decline on the run, she may look to maintain a higher carb intake on the run and increase the relative sodium concentration of her fluids throughout.
PF&H

Laura's full stats

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Overall
836g total carb
93g per hour
8,890ml total fluid
988ml per hour
2,873mg total sodium
319mg per hour
323mg
Sodium per litre
1160mg total caffeine
19.0mg per kg
Bike and Run
Bike
Run

Data Confidence
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We rate each of our case studies from 1-5 based on the level of accuracy, and our confidence in the data.
1
2
3
4
5

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.

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