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David Lipman's scorecard

London Marathon

Sunday 23rd April, 2023

Within recommended ranges

Just outside recommended ranges

Significantly outside recommended ranges

  • 78g

    Carb per hour
  • 0mg

    Sodium per hour
  • 56ml

    Fluid per hour
  • 0mg/L

    Relative sodium concentration
  • 2.38mg/kg

    Caffeine per bodyweight
  • How David hit those numbers

    2 x Bagel with Peanut Butter and Banana
    1 x Sodium Bicarb (40g Carb, 5200mg sodium)
    1 x Black Coffee
    500ml x Water and 6g Taurine
    2 x PF 30 Energy Gel
    2 x PF 30 Caffeine Gel
    1 x PF 90 Energy Gel
    150ml x Plain water

    How David's hydration and fueling went...

      • 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”


      • 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


    Quick Carb Calculator Recommendation


    carb 30 mins before


    carb per hour during
      • Dave executed a solid carb load where he aimed to consume ~10 grams per kg of bodyweight in the couple of days before the race. This falls perfectly within the 8-12g recommended dose to optimally fill his glycogen stores, and you can see an example of the things Dave used to hit this in their blog post on carb loading with a Supersapiens
      • Then, shortly before the race we would usually recommend a small carbohydrate hit to peak Dave’s blood glucose levels optimally and spare this stored glycogen for later in the race. However, having tested this using Supersapien’s continuous glucose monitor, he found he was experiencing rebound hypoglycemia when taking any carbs within 2-3 hours of exercise, so chose to rely on his carb-heavy breakfast alone, instead of combining this with a pre-race gel
      • During the race Dave took two PF 30 Gels, two PF 30 Caffeine Gels and a PF 90 to average ~78g of carb per hour. This is slightly below the 90g/h recommended by our Fuel & Hydration Planner, but his energy levels were high all day, and his glucose trace reflects this suggesting he fueled adequately
      • Dave’s caffeine intake was also decent, with a large black coffee pre-race to get his blood caffeine levels up, followed by a further 200mg mid-race from Caffeine Gels. He averaged ~2.38mg per kg of bodyweight, which is slightly below the 3-6mg/kg recommended by the literature, but as the race was only 2 hours 42 minutes long, it’s likely this was enough to reap the performance benefits associated with caffeine


      • 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!

    Key info

    David Lipman

    Sweat sodium concentration
    Sweat sodium classification
    * determined by a PH Advanced Sweat Test


    Overall Time

    Event information

    London Marathon
    London, England
    23rd April, 2023
    Total Distance
    42.2km / 26.2mi

    Race conditions

    Weather Conditions
    Min Temp
    10°C / 50°F
    Max Temp
    15°C / 59°F
    Avg Temp
    13°C / 55°F

    Athlete feedback

    Race Satisfaction
    Hydration rating
    I don't usually drink much during races, but I never felt thirsty
    Energy levels
    Toilet stops
    GI comfort
    The best my stomach has felt in a marathon so far
    Twinges but not full-on cramps

    David's Thoughts

     Tough, but I loved it!

    David's full stats

     Carbohydrate (g)Sodium (mg)Fluid (ml)Caffeine (mg)Relative sodium concentration (mg/L)
    Total intake21001502000
    Per hour7805674

    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).

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