Mark Threlfall
Berkeley Marathons
Mark's headline numbers
Mark'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.
Mark’s main source of carbohydrate came from PF 30 Chews, plus a few energy bars and the small amount in PH 1500 (Drink Mix). After the first lap, he also treated himself to an unusual mid-race snack, a pork pie! In races of this length and relative intensity ‘real foods’ are used more frequently as a source of fuel. Unfortunately, Mark’s ankle flared up halfway through the second marathon after twisting it earlier in the day, causing him quite a bit of pain and nausea. Because of this, he consumed less carbs than planned, leading to a lower than ideal average intake compared to the scientific recommendations.
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 Mark’s losses are Very High (1,474mg/L), nailing his hydration strategy becomes especially crucial when it’s hot and/or humid.
Learn moreMark completed two laps (~43km each) and carried two Soft Flasks on each, with both containing a sachet of PH 1500 (Drink Mix) in 500ml of water. After he finished these, he switched to Electrolyte Capsules and plain water that he picked up from either water fountains or nearby pubs (one of which he stopped at briefly to enjoy a well-deserved glass of cola). Considering Mark’s high sweat sodium concentration and sweat rate, he would likely have benefited from increasing both his fluid and sodium intake to match his losses more closely and avoid symptoms of dehydration, especially if he were to go for a third or fourth lap.
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.
Mark doesn’t tend to consume caffeine during races, as it more often than not causes him GI issues. Despite this, he planned on having a few PF 30 Caffeine Gels throughout the race to help boost his focus and sustain energy as the day progressed. Ultimately, he decided to avoid caffeine entirely as he wasn't able to push the pace or distance because of the ankle injury and was already battling nausea. Other than some cola, Mark’s caffeine intake was pretty low across the day. It’d be worth practising his original plan of using caffeine during some higher intensity training sessions to see if it’d be a viable strategy in future long races.
How Mark hit his numbers
Here's everything that Mark ate and drank on the day...
Mark's weapons of choice
Final thoughts
Mark
PF&HMark's full stats
Data Confidence?
There is good confidence in the accuracy of the data reported. An athlete feels that the numbers closely reflect what they consumed despite a couple of estimations which may carry some degree of error. The majority of what was consumed is recorded to a high level of specificity (most volumes are known through the use of bottles brands quantities flavours). The numbers are very plausible and align with previous data recordings (if an athlete has collected data previously).