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Alex Leprêtre's scorecard

London Marathon

Sunday 23rd April, 2023

Within recommended ranges

Just outside recommended ranges

Significantly outside recommended ranges

  • 67g

    Carb per hour
  • 0mg

    Sodium per hour
  • 111ml

    Fluid per hour
  • 0mg/L

    Relative sodium concentration
  • 0mg

    Total caffeine
  • How Alex hit those numbers

    500ml x PH 1500 (Tablet)
    1 x Bowl of Porridge with Honey
    1 x Black coffee
    1 x Banana
    1 x Espresso Shot
    1 x PF 30 Energy Gel
    4 x PF 30 Energy Gel
    250ml x Plain water

    How Alex's hydration and fueling went...

      • Alex is a lawyer by day and runner by night, competing both internationally, and for the Highgate Harriers running club in London
      • With impressive personal bests over the 5km (13:55) and 10km (30:18) and Half marathon (63:28), Alex was hoping to carry this speed across to his debut marathon at London 2023
      • As this was the first event Alex has ever had to think about fueling or hydrating during, he worked with the PF&H Sports Science team in advance to prepare his strategy
      • Amazingly, despite his impressive running pedigree, Alex did not secure an elite start position, meaning he began the race with the 40,000 non-elite starters, of which only two beat him on the day. This meant Alex barely saw another runner for the 42.2km, and wasn’t able to run in a pack like the pros


      • Alex understood that starting endurance events dehydrated is actually a very common performance limiting issue, and so decided to try and start optimally hydrated by preloading with a PH 1500 both the night before and morning of the marathon
      • This ‘preloading’ helps performance by encouraging retention of water within the blood plasma, so the cardiovascular system doesn’t have to work any harder than absolutely necessary. Alex has also found that this retention has reduced the feeling of needing to pee mid-race
      • With the context of his excellent pre-hydration, combined with the mild (13°C / 55°F) and rainy weather, it wasn’t surprising to hear that Alex never felt particularly thirsty throughout this race
      • This is because there was less need for the body to offload excess heat through sweating, and therefore less fluid loss needed to be replaced in order to keep him above 2% body weight loss, which is generally thought to be where performance declines start to occur
      • While he only drank ~250ml (8oz) of plain water across the two and a quarter hours, we would still recommend drinking some electrolytes, in order to get sodium on board while running
      • One of the main reasons for this is the key role that sodium plays in assisting with carbohydrate absorption, via ‘glucose sodium cotransporters
      • Happily, on the day Alex experienced no cramping and rated his hydration strategy a strong 7 (out of 10)


    Quick Carb Calculator Recommendation


    carb 30 mins before


    carb per hour during
      • As someone who has always specialised in shorter distance races, this was the first event in which Alex needed to consume fuel while on the move
      • Alex followed the advice of the PF&H Sports Scientists to a tee and Carb loaded in the days building up to the race, culminating in a ‘pasta party’ the night before, and a breakfast of porridge and a banana
      • He naturally understood the requirement during longer events for additional carb while burning so much energy (running at 3:16 mins per km) and so incorporated gut training into his marathon-specific sessions to make this as comfortable as possible on race day
      • His strategy on the day was straightforward. He had one gel ~20 minutes before the clock hit zero and then had a PF 30 Gel every 25 minutes until 1:35
      • He was due to have an additional gel at ~2 hours but felt full, which he’s attributing to his large tomato pasta dinner the night before. The additional carb in this gel would have pushed his average intake up from ~67g per hour to 80g/h (closer to the Fuel and Planner’s 90g/h recommendation)
      • Despite making the confident decision to skip this final PF 30 Gel, Alex rated his debut marathon energy levels as an 8 (out of 10) with a bit of a lull towards the end of the race, but certainly no ‘wall’ or ‘bonk’ in sight
      • Alex may want to optimise his future intake by making the most of caffeine and its performance associated benefits. His two coffees in the morning would have contributed somewhat, but a PF 30 Caffeine Gel or two, instead of regular gels may have helped reduce his perceived exertion and increase focus


      • Alex was satisfied to run a 2:15:01 in his debut marathon, and beat all but two other people from the mass start pen to the finish line. He’s also confident that he’ll be able to beat this time when he lines up for the Berlin Marathon a few months after this race
      • He did very well to average ~67g of carb per hour in the first race he’s ever had to eat and drink during, rating his gastrointestinal comfort at an 8 (out of 10), only getting some discomfort when swallowing some air with his water
      • Looking forwards Alex will be able to optimise his use of caffeine, and continue gut training so he is happy tolerating additional carb towards the end of a marathon

    Key info

    Alex Leprêtre



    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 clearly didn't take in much water, but also didn't feel thirsty or dehydrated on such a mild, rainy day
    Energy levels
    My energy was really good, I struggled a bit towards the end but wouldn't put this down to fueling
    GI comfort
    Only a slight bit of discomfort when drinking water and swallowing some air at the same time
    No cramping

    Alex's Thoughts

     I am satisfied with this result, but think if all goes well I can run 2-3 minutes quicker in Berlin

    Alex's full stats

     Carbohydrate (g)Sodium (mg)Fluid (ml)Caffeine (mg)Relative sodium concentration (mg/L)
    Total intake150025000
    Per hour6701110

    Data Confidence







    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.

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