• Dave is the Director of Applied Science and Content at Supersapiens and part of the SuperPrecise team boxing off Spring marathons in 2023
• He set a shiny new personal best marathon time at London running 2:42:53, all the while crushing his fueling plan to a tee, and drinking more than he’s ever done during this distance race
• Dave rated his race satisfaction a maximum 10 (out of 10) and ran “on the limit” the whole way, saying it was “his toughest marathon to date”

Hydration

• Dave didn’t complete our usual preloading protocol, but did take some sodium bicarb with his breakfast which contained a very large dose of sodium (~5,200mg) and ~40g of carbohydrates. Thankfully this extreme dose didn’t cause him any gastrointestinal (GI) issues like high doses of sodium often does. We’d recommend a relative sodium concentration of ~1,500mg per litre (32oz) the night before and morning of the race as research has shown this to be an optimal concentration for inducing hypervolemia, whilst ensuring optimal hydration and minimising the risk of GI distress
• This could have been added to the 500ml (16oz) bottle of water he drank on the train to the start line ~60 minutes before the race began. Interestingly, Dave also felt like he needed to pee a couple of times before the race, which can sometimes be prevented by adding some sodium to his pre-race drink
• Being well-versed on the fueling side of his performance, Dave is working on increasing his fluid intake alongside his carbs to help prevent dehydration towards the end of the race. In London he drank the most he ever has during a marathon, but still only averaged ~56ml (2oz) of water per hour
• Despite temperatures being mild, this is a very small intake compared to the average consumption from all of our marathon case studies which is ~356ml (12oz) per hour. Of these 36 case studies, 30 of them were also completed in cold or mild conditions, so potentially something for Dave to focus on in future races
• Dave did start to experience some minor cramps in his hamstrings at ~37km (24 miles), and as we know he loses 1,003mg of sodium in each litre of his sweat, this puts him in the moderate saltiness camp. As he didn’t take any electrolytes during the race, perhaps including some sodium may have helped prevent these muscle cramps
• For future races, Dave might look to increase his fluid intake, and adding some sodium could also help his carbohydrate absorption rate. He could do this by carrying some Electrolyte Capsules with him and swallowing them as he picks up water from the on-course aid stations

Fueling

Conclusions

• Dave’s fuel and hydration strategy was solid, with some minor areas to optimise going forward like taking more fluid, and including some electrolytes to help with carb absorption
• As the final member of the 2023 SuperPrecise marathon squad to complete their 26.2 miles, his finish time of 2 hours 42 minutes is also the average finish time for the five runners - kudos Dave!