Simen's headline numbers
Carbohydrate is the main fuel you burn when racing. Failing to fuel properly is a leading cause of underperformance in longer races.
As an experienced ultra runner who has only recently dialled in his fueling strategy, Simen has been used to eating anything from burgers and fries to milkshakes and beer during events. Now that he’s using his fuel strategy to help take his performance to the next level, it’s important to strike the right balance between gels and energy drink mixes which have been designed specifically to be easily tolerated by the gut and provide maximal fuel to the working muscles, and real foods which he could look forward to as something different and would satiate him for a few hours. As he said, he largely nailed this during this race, but could perhaps have done with a little more energy provision through the colder nighttime hours when his drive to eat was reduced and he went from hitting ~60g an hour to as low as ~19g at some points.
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.
Given Simen’s losses are High (1,310mg/L), nailing his hydration strategy becomes especially crucial when it’s hot and/or humid.Learn more
During this extreme event which involved running for two days and two nights, Simen’s fluid requirement fluctuated significantly alongside his sweat rate, which increased in the heat of the day, and reduced overnight when temperatures fell and heavy rain arrived. For the most part he adjusted his intake well, but he did overdrink in the first three hours (~850ml per hour) which resulted in him going to the toilet several times. Although his subjective feedback was positive and he didn’t experience any noticeable side effects, Simen also significantly under-replaced sodium compared to his relatively high losses, and would have needed the equivalent of 40 to 50 additional Electrolyte Capsules throughout the 41 hours of running in order to match his losses more closely.
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.
While the absolute value of Simen’s caffeine intake exceeds the general recommendations listed above, the research which supports these guidelines are based on single day efforts, and so don’t take into account events of this duration. By delaying taking any until the evening, Simen timed his caffeine intake extremely well to effectively battle his circadian rhythm, and make him more alert during the times when his body was trying its hardest to go to sleep.
How Simen hit his numbers
Here's everything that Simen ate and drank on the day...
Simen's weapons of choice
Simen's full stats
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.