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Mark Southgate's scorecard

Boston Marathon

Monday 18th April, 2022

Within recommended ranges

Just outside recommended ranges

Significantly outside recommended ranges

  • 64g

    Carb per hour
  • 532mg

    Sodium per hour
  • 553ml

    Fluid per hour
  • 961mg/L

    Relative sodium concentration
  • 8.06mg/kg

    Caffeine per bodyweight
  • How Mark hit those numbers

    500ml x Water with PH 1500 (Drink Mix) and an energy drink mix
    1 x Bowl of porridge
    1.5 x Mug of black coffee
    1 x Banana
    1 x Bagel with peanut butter and jam
    1 x Caffeine tablet (100mg caffeine)
    1 x Energy Gel with caffeine (24g carb, 100mg caffeine)
    1.4L x Plain water
    3 x Energy gel (25g carb)
    1 x Energy Gel with Caffeine (25g carb, 100mg caffeine)
    500ml x Energy drink (22g carb)
    2 x Energy Gel with caffeine (24g carb, 100mg caffeine)
    1 x Energy Gel with caffeine (18g carb, 100mg caffeine)
    2 x Electrolyte capsule (450mg sodium)

    How Mark's hydration and fueling went...

      • Mark Southgate, a long-time PF&H customer and a keen runner, enjoyed a great marathon at Boston in which he ran extremely close to his personal best time
      • Prior to race day, Mark booked a one-to-one video call with our Athlete Support Team to help finalise his hydration and fueling strategy, giving him time to try out his plan beforehand in training
      • Mark felt “very happy” with his fueling and hydration which all went perfectly to plan on the day. However, Mark felt he hadn't prepared his legs for the amount of descent on the Boston Marathon course, which consequently impacted his performance


      • Ahead of the race, Mark preloaded effectively with PH 1500 both the night before and on the morning of the race which helped ensure that he was starting optimally hydrated with maximal blood volume
      • During the race, Mark picked up roughly 19 cups of fluid (~100ml/3oz each) provided at aid stations on course, resulting in a total consumption of ~1.9L/66oz of fluid. This broke down into ~1.4L/47oz plain water and ~500ml/16oz of sports drink that averaged a fluid consumption of ~553ml per hour (18oz/hr)
      • We don’t have data on Mark’s sweat rate, but he described his sweat losses as moderate during the race. Considering the cool conditions (~11℃/51°F), an hourly intake of this volume would more than likely have replaced an adequate proportion of his sweat losses
      • From the energy drink that Mark was able to pick up on course, as well as the energy gels he had with him, he was able to consume a total of ~1826mg of sodium - averaging ~532mg per hour. We don’t know Mark’s sweat sodium concentration as he hasn’t had a Sweat Test but in relation to his fluid intake, the relative sodium concentration of Mark’s intake was ~961mg/L, which is close to the average sweat sodium concentration that we see from from our Sweat Test. This was a proactive level of replacement for a marathon in cold conditions


    Quick Carb Calculator Recommendation


    carb 30 mins before


    carb per hour during
      • Although Mark didn’t set off until 10:30am, he had to start his day early (6:00am) to catch the bus and therefore he had his breakfast earlier than he normally would before a race. Mark's fueling strategy began at 6:30am when he consumed a large bowl of porridge, washed down with one and a half cups of black coffee, followed an hour later by a bagel and a banana. This is a substantial breakfast with a high carb content which, along with the coffee, will have helped maximise his glycogen stores and energy levels ahead of the race
      • An hour before the race, Mark consumed ~500ml/16oz of PH 1500 combined with an energy drink mix, and a 100mg caffeine tablet
      • Mark also took an additional 24g of carbs in the form of an energy gel in the last 30 minutes before racing - we've seen other marathon runners use this technique to increase carbohydrate availability in the early stages of a race, but this tactic will come down to personal preference
      • During the run, Mark consumed an energy gel every 25 minutes, in total taking seven gels (four of which were caffeinated)
      • Using this strategy, he hit an average of ~64g carb per hour which met our Quick Carb Calculator’s recommendations of 60-90g/hr for a race of this duration and intensity. Due to the positive association between carb intake and performance, if Mark is able to further increase his intake in future races this could benefit his overall performance
      • On top of his pre-race caffeine gel, Mark also consumed a total caffeine dose of ~500mg during the race (including his final pre-race caffeine gel). When taking into consideration his bodyweight, this equated to a dosage of ~8.06mg of caffeine per kg
      • This dosage is above the general caffeine recommendations of 3-6 mg of caffeine per kg of bodyweight for enhancing endurance performance. Whilst a higher dose may not be detrimental to Mark, studies have shown that ingesting doses greater than 6mg/kg don't reap any further performance benefits. So, whilst this wasn’t a cause for concern, Mark may opt to use less caffeinated gels in future races


      • Mark raced well at the Boston Marathon and executed a well structured fueling and hydration plan to keep up with his personal best pace for most of the race
      • He fueled well before and throughout the race with carb-rich foods and gels to meet the recommended carb intake of 60-90g/hr, whilst not experiencing any GI issues
      • In future, Mark could reduce his caffeine intake to within the recommended guidelines, especially if he experienced any disturbances to his sleep following the race
      • Overall, Mark rated his race satisfaction as 7 out of 10 (due to the lack of preparation he'd done for the elevation) and we look forward to seeing how he adapts his plan to a full distance triathlon at IM Chattanooga in September

    Key info

    Mark Southgate



    Overall Time

    Event information

    Boston Marathon
    Boston, USA
    18th April, 2022
    Total Distance
    42.2km / 26.2mi

    Race conditions

    Weather Conditions
    No Rain
    Min Temp
    5°C / 41°F
    Max Temp
    9°C / 48°F
    Avg Temp
    9°C / 48°F

    Athlete feedback

    Race Satisfaction
    Hydration rating
    Very happy with my hydration as I has no issues at all
    Energy levels
    Absolutely fine, my only set back was sore muslces from the ascents and descents
    Toilet stops
    GI comfort
    No cramping

    Mark's full stats

     Carbohydrate (g)Sodium (mg)Fluid (ml)Caffeine (mg)Relative sodium concentration (mg/L)
    Total intake2211,8261,900500961
    Per hour64532553146

    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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