Floris Gierman
Chicago Marathon
Floris' headline numbers
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.
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.
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 moreFloris 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.
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
PF&HFloris' full stats
Data Confidence?
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.