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Floris Gierman

Chicago Marathon

9th October, 2022
United States
Chicago
Running, Marathon - 42.2km
15°C
, Mild
2hrs 52mins
more race details

Floris' headline numbers

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~94
g
Carb per hour
Recommended 90g/h+
~209
ml
Fluid per hour
Recommended 100-500ml/h
~1,250
mg
Sodium per litre
Recommended 400-800mg/L
~5.8
mg
Caffeine per kg
Recommended 3-6mg/kg

Floris' 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
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T - 15mins: Took in a final dose of carb
Carb per hour
Recommended 90g/h+
~94
g
Floris' Energy Rating
10
/10
"I felt mentally alert due to increasing my fuel and caffeine compared to prior races. "
Our thoughts

While on the course, Floris’ took eight gels in total, alternating between regular PF 30 Gels and PF 30 Caffeine Gels. He was inspired to increase his carbohydrate intake for this race compared to previous marathon efforts after speaking to UTMB winner Kilian Journet on his podcast. Undoubtedly, along with the boost he felt from running in front of a “great crowd”, his consistent carb intake will have contributed to his perceived energy levels being so high, especially in the latter stages of the run. Despite his training volume for this race “not being that high” by his standards, peaking at around 55-60 miles per week (including some pickleball sessions with the family), Floris' over 90g/h intake supported him in running through the halfway mark at 1:27:30 and run a ‘negative split’ to the finish - even clocking a 6:15 minute mile right at the end of the race!

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.

Floris635mg/L
Floris has been Sweat Tested to dial in his 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 Floris’s losses are on the low side, getting his hydration strategy right is still important if he wants to perform at his best.

Learn more
Pre-loaded electrolytes
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T - 60mins: Drank ~500ml of strong electrolyte drink
Fluid per hour
Recommended 100-500ml/h
~209
ml
Sodium per litre
Recommended 400-800mg/L
~1,250
mg
Our thoughts

Floris made sure that he utilised 10 of the aid stations throughout the marathon by picking up cups of water and having a couple of sips from each. This meant that he had an overall fluid intake of ~600ml, averaging out to ~209ml per hour. On this occasion, given the temperate conditions and Floris’ own perceptions of his fluid losses during the race - it is likely that this volume was appropriate, but it’s something we’d definitely see increase when Floris competes in warmer races in future. Floris cleverly taped single Electrolyte Capsules to his PF 30 Gels so that he wouldn’t have to fumble around in his pockets to access them. By taking three capsules he was able to maintain a relative sodium concentration of ~1,250mg/L (mg/32oz), despite this being slightly over Floris' Sweat Sodium Concentration, as he didn't have any major hydration issues or effects of 'oversalting' it's likely Floris did well to replace his losses. However, in future races, Floris could consider dialing this back slightly.

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
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T - 0-4hrs: Had a final hit of caffeine
Caffeine per kg
Recommended 3-6mg/kg
~5.8
mg
Our thoughts

Floris consumed ~400mg of caffeine during the race. This would put someone of his size within the recommended intake of 3-6mg/kg so we wouldn't suggest he changes anything.

How Floris hit his numbers

Here's everything that Floris ate and drank on the day...

Floris' weapons of choice

Final thoughts

Floris' Satisfaction Rating
10
/10
My aim was to finish strong and healthy after some health challenges in the early stages of the training cycle, so this race felt great!
Floris
Floris did extremely well to execute a solid fuel and hydration strategy for the Chicago Marathon. In part, it will have contributed to his high reported energy levels and reports of no cramping. This race undoubtedly ticked all the boxes Floris wanted it to, with the aim of finishing “strong and healthy” and increasing his carb intake, he did just that and had what he described as his “most fun race day experience ever”.
PF&H

Floris' full stats

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Overall
270g total carb
94g per hour
600ml total fluid
209ml per hour
750mg total sodium
262mg per hour
1,250mg
Sodium per litre
400mg total caffeine
5.8mg per kg

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.
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2
3
4
5

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.

Floris' recent case studies

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