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Chris Harris' scorecard

Manchester Marathon

Sunday 16th April, 2023

Within recommended ranges

Just outside recommended ranges

Significantly outside recommended ranges

  • 79g

    Carb per hour
  • 938mg

    Sodium per hour
  • 454ml

    Fluid per hour
  • 2,066mg/L

    Relative sodium concentration
  • 4.17mg/kg

    Caffeine per bodyweight
  • How Chris hit those numbers

    1 x PF 30 Gel
    500ml x PFH 1500 (Drink Mix)
    1 x Porridge Pot + Honey
    1 x PF 30 Caffeine Gel
    500ml x Two Servings of PH 1500 (Drink Mix)
    4 x PH Electrolyte Capsule
    2 x PF 30 Caffeine Gel
    1 x PF 90 Energy Gel
    710ml x Plain water

    How Chris' hydration and fueling went...

      • Chris ‘Minty’ Harris is a Sports Scientist at PF&H, and self professed triathlon nerd. After a solid outing at the IRONMAN World Championships in Kona, Minty decided to turn his attention to completing a standalone marathon
      • As part of the #SuperPreciseCrew, Chris travelled up the country from our Dorset HQ to Manchester marathon and wore a continuous glucose monitor from Supersapiens throughout the race to monitor his fueling
      • With a pre-race aim of running sub 2:45, he was incredibly satisfied to run a 2:40:53 on the day, and has already got his eyes set on breaking into the 2:30’s at his next race


      • As he preaches on all of his athlete video calls, Chris knew that he would have to preload using PH 1500 strength electrolytes in order to start optimally hydrated
      • After doing this both the night before and morning of the race, Minty started the race with a 500ml Soft Flask containing two PH 1500 (packets) which saw him through to 30km (18.6 miles)
      • After this, he relied on picking up water from aid stations, and four Electrolyte Capsules, in an effort to keep his electrolyte intake in line with his above average sweat sodium losses (we know from his Sweat Test that he loses 1,433mg/L)
      • In total, this meant that Minty averaged ~454ml (15.3oz) of fluid per hour, with a very high relative sodium concentration of ~2,066mg/L (mg/32oz)
      • While this electrolyte replacement strategy was potentially too aggressive on this occasion, Chris was pleased to report no electrolyte related cramping, and rate his hydration strategy a 9 (out of 10)
      • Minty did complain of some slight muscle twinges in his right calf with about 3km (1.9 miles) left of the race, however he attributed these to his six hour car journey the day before the race and that some muscles didn’t feel like they were firing as well as he usually expects
      • The only way Minty would have improved his hydration strategy on the day was to drink more fluid, if this was plain water it would also have helped bring his relative sodium concentration down, more in line with his individual losses


    Quick Carb Calculator Recommendation


    carb 30 mins before


    carb per hour during
      • Minty was joined by Ant Gritton from the PF&H marketing team for dinner, as they enjoyed a pizza the night before, they topped off their carbohydrate stores and talked about pacing strategies before an early pre-race bedtime
      • Well rested, Chris made final contributions to his carb load via porridge and honey for breakfast, as well as a PF 30 Gel
      • He then had a final PF 30 Caffeine Gel 15 minutes before the race start, to boost his blood glucose availability. This can be seen in his Supersapiens glucose trace, and would have had the effect of sparing his stored glycogen for slightly later on
      • During the marathon, Minty sipped on a PF 90 (Jumbo Gel) throughout the first 24km (15 miles), to keep his available energy as high as possible. He also boosted this with two PF 30 Caffeine Gels at 11km (6.8 miles) and 31km (19.3 miles)
      • This resulted in him having an overall intake of ~79g of carb per hour, which is slightly below the Fuel & Hydration Planner’s 90g per hour recommendation. Despite this he still perceived his energy levels on the day a perfect 10 (out of 10) and exceed the ceiling of his Supersapiens observable glucose score for a prolonged period of time during the race
      • Minty did say that he’d have taken an extra gel, having finished his last one at 32km (19.9 miles). The logistics of carrying all of his own fuel in his shorts made this especially difficult
      • With ~300mg total caffeine intake, Minty consumed ~4.17mg per kilo of bodyweight. This is well within the general 3-6 mg/kg recommended guidelines for performance enhancement, and would have aided his focus and perceived exertion out on the course


      • Chris was very pleased with his significantly faster than planned 2:40:53 debut standalone marathon time, and was very satisfied he could report no electrolyte related cramping (avoiding having to pay the PF&H team fine in the process)
      • From a fueling perspective, Chris is extremely pleased with his perceived energy levels through the race and is looking forward to the next chance he can get to put this strategy to the test
      • In future, Minty is planning on arriving at the race venue a couple of days before, to ensure any prolonged travel doesn’t affect his body too much. He’ll also potentially be more willing to drink more fluid, especially in warmer weather

    Key info

    Chris Harris

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


    Overall Time

    Event information

    Manchester Marathon
    Manchester , England
    16th April, 2023
    Total Distance
    42.2km / 26.2mi
    Total Elevation
    140m / 459ft

    Race conditions

    Weather Conditions
    Min Temp
    8°C / 46°F
    Max Temp
    11°C / 52°F
    Avg Temp
    10°C / 50°F

    Athlete feedback

    Race Satisfaction
    Hydration rating
    A bit thirsty towards the last 20 minutes, but it wasn't that hot so wasn't sweating much
    Energy levels
    No dips, solid fueling
    Toilet stops
    GI comfort
    Felt great throughout
    Mild cramps that I could push through

    Chris' Thoughts

     As a first stab at the marathon, I'm over the moon but I've got a few things to work on for my next one

    Chris' full stats

     Carbohydrate (g)Sodium (mg)Fluid (ml)Caffeine (mg)Relative sodium concentration (mg/L)
    Total intake2102,5001,2103002,066
    Per hour79938454113

    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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