Joe's headline numbers
Joe'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.
Joe averaged just under 60g/h of carbohydrate during the race, which kept his energy levels stable up until the last stretch. His intake falls below the recommended carb dose for a race of this duration and intensity (ideally 90g/h), so increasing his fueling in future events could help optimize his performance. Research, as well as anecdotal evidence from our case study database, suggests that higher carb consumption enhances endurance performance, provided it doesn’t cause stomach discomfort. To improve tolerance, Joe may benefit from training his gut by gradually increasing his intake in key training sessions. He used a mix of gels and bars to fuel, with a goal of eating at least every 10km to help prevent prolonged gaps in fueling. However, around 42km into the race, Joe was sick and attributed this to a sudden increase in pace while chasing a marathon PB. Though he recovered quickly, vomiting may have contributed to his late-race energy dip by reducing the amount of carbohydrate available for absorption.
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.
Given Joe’s losses are High (1,208mg/L), nailing his hydration strategy remains important, even when it’s Cold.
Learn moreJoe finished the race with a -2.88% change in body weight, reinforcing the widely accepted view that most endurance athletes can tolerate 2-4% dehydration without major performance decline. Considering his average sweat rate of ~1L per hour during the race, increasing his fluid intake closer to 500ml/h may have been beneficial, though he felt no problems pushing over 2% body weight change. The relative sodium concentration of his drinks was lower than his sweat sodium concentration, so we’d recommend slightly increasing this to be more in line with his losses for warmer races. With the cooler conditions though, Joe was able to adjust his intake on the go, skipping planned Electrolyte Capsules as he felt adequately hydrated and experienced no cramping, indicating this strategy worked well for him on the day.
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.
Joe consumed ~316mg of caffeine during the race and also pre-caffeinated with a strong coffee in the morning. This falls within the recommended range of 3-6mg per kilogram of body weight, a dosage shown to enhance endurance performance by reducing perceived effort and masking fatigue.
How Joe hit his numbers
Here's everything that Joe ate and drank on the day...
Joe's weapons of choice
Final thoughts
PF&HJoe's full stats
Data Confidence?
There is a high level of confidence in the accuracy in the data. The numbers presented are believed to be a very close reflection of reality. There may still be one or two estimations made in the data (an inescapable part of field data) but there is reason to believe that these are accurate and that possible error has been kept to a minimum. It is data that has been collected and recalled as accurately as is possible given the uncontrolled settings/circumstances.