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Jack Davis' scorecard

Paris Marathon

Sunday 2nd April, 2023

Within recommended ranges

Just outside recommended ranges

Significantly outside recommended ranges

  • 70g

    Carb per hour
  • 414mg

    Sodium per hour
  • 331ml

    Fluid per hour
  • 1,250mg/L

    Relative sodium concentration
  • 2.53mg/kg

    Caffeine per bodyweight
  • How Jack hit those numbers

    500ml x PH 1500 (Tablet)
    1 x Baguette with Honey
    1 x PF 30 Gel
    5 x PH Electrolyte Capsule
    1 x PF 30 Gel
    2 x PF 30 Caffeine Gel
    1 x PF 90 Gel
    1L x Plain water

    How Jack's hydration and fueling went...

      • Jack is the newest member of the PF&H team and Paris was his first standalone marathon having run the distance twice but only at the end of an IRONMAN triathlon. You can actually see how Jack’s strategy compares to his case study at his most recent IRONMAN in Utah
      • He crushed his pre-race fuel and hydration plan and finished just outside of his target time of three hours, having been on-track until some painful muscle fatigue in the latter kilometres slowed him down


      • Jack may be new to the team, but understood the importance of preloading his sodium levels to ensure he started optimally hydrated. To do this, he emptied a PH 1500 packet into 500ml of water, and finished it around an hour before the race started
      • During the race itself, Jack regularly picked up plain water from the aid stations, totalling ~1L (32oz) across the race
      • To ensure he replaced a good proportion of his electrolyte losses, Jack carried some Electrolyte Capsules with him, taking five throughout the race. This meant the relative sodium concentration of his fluid intake was ~1,250mg per litre (mg/32oz)
      • As Jack’s sweat sodium concentration, measured by our Sweat Test, is 983mg/L (mg/32oz), he did a good job of electrolyte replacement, but could perhaps have increased his fluid intake a little to reduce the saltiness to be more in line with his sweat losses


    Quick Carb Calculator Recommendation


    carb 30 mins before


    carb per hour during
      • Jack began the race fully stocked on glycogen after a strong carb-load for the 48 hours prior, finishing with a small amount of honey on a freshly baked French baguette
      • He then initiated some glycogen sparing by taking his PF 30 Gel around 20 minutes before the gun went off, which will have helped him maintain good energy levels later in the race
      • The timing of this pre-race gel is something Jack has helped to dial in by using a continuous glucose monitor from Supersapiens, and found optimal increases in blood glucose occurred between 15-25 minutes after intake, so chose to utilise this for the race
      • His fueling strategy during the race was simple, taking ~30 grams of carb every 25-30 minutes. Jack sipped on a PF 90 in the first half, then consumed two PF 30 Caffeine Gels and a non-caffeinated PF 30 Gel in the back half
      • Overall, his average carb intake was ~70g per hour, which is slightly below the amount we’d recommend for an event of this duration and intensity, which is between 75-90g per hour
      • Jack managed to keep his perception of energy high, likely due to a combination of his regular carb and caffeine intake. His caffeine intake was again, slightly below the 3-6mg/kg recommended in the literature to achieve maximal benefit, but at 2.5mg/kg, he would still have seen a reduction in perceived effort


      • Overall, Jack’s first ever standalone marathon went very much to plan, with only his total time slightly falling below what he’d hoped
      • From a fueling and hydration perspective, Jack took great confidence in how well he executed his plan, and put the slight fade in pace towards the end down to muscle fatigue

    Key info

    Jack Davis

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


    Overall Time

    Event information

    Paris Marathon
    Paris, France
    2nd April, 2023
    Total Distance
    42.2km / 26.2mi
    Total Elevation
    269m / 883ft

    Race conditions

    Weather Conditions
    Min Temp
    6°C / 43°F
    Max Temp
    8°C / 46°F
    Avg Temp
    7°C / 45°F

    Athlete feedback

    Race Satisfaction
    Hydration rating
    Energy levels
    Toilet stops
    GI comfort
    Twinges but not full-on cramps

    Jack's Thoughts

     My fuel and hydration plan felt spot on, muscle fatigue was my main limitation towards the end but overall I'm happy

    Jack's full stats

     Carbohydrate (g)Sodium (mg)Fluid (ml)Caffeine (mg)Relative sodium concentration (mg/L)
    Total intake2101,2501,0002001,250
    Per hour7041433166

    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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