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Ruth Astle's scorecard

IRONMAN® South Africa

Sunday 21st November, 2021

Within recommended ranges

Just outside recommended ranges

Significantly outside recommended ranges

  • 37g

    Carb per hour
  • 325mg

    Sodium per hour
  • 627ml

    Fluid per hour
  • 518mg/L

    Relative sodium concentration
  • 0.68mg/kg

    Caffeine per bodyweight
  • How Ruth hit those numbers

    1 x Sachet of coconut jasmine rice with honey
    1 x Tea
    1 x Coffee
    500ml x Energy drink mix (79g carb)
    *** Tip: For sea swims, put a bottle of water at T1 to rinse your mouth out
    1L x PH 1500 (Tablets)
    1.5L x Plain water
    500ml x Energy drink mix (79g carb)
    375ml x Premade energy drink mix (225g carb)
    1.5L x Plain water
    3 x Energy gel (25g carb)
    200ml x Energy drink mix (32g carb)
    300ml x Cola
    50ml x Red Bull

    How Ruth's hydration and fueling went...

      • Five weeks after winning her first IRONMAN race as a pro triathlete at IM Mallorca, Ruth recorded a second full-distance victory with a fantastic performance at IM South Africa, where she won in a time of 8 hours and 38 minutes!
      • In tough, warm and extremely windy conditions (which lead to the swim being shortened to 1.9km), Ruth came out of T2 leading and ran a 3:11:55 marathon to finish ahead of the chasing Annah Watkinson
      • In what Ruth described as “without doubt my hardest IRONMAN to date”, she used similar products to fuel and hydrate as to her previous races but consumed less in total


      • On the bike, Ruth had two bottles (750ml/25oz and 500ml/16oz) of energy drink mix but only drank half of the 750ml/25oz bottle. She also picked up around ~250ml/8oz at 10 aid stations and added PH 1500 to a proportion of this. On the run, she had two pre-made energy drink mix bottles which she drank ~100ml/4oz of each and picked up some Coca Cola and Red Bull from a few aid stations
      • As a result, Ruth drank an average of ~627ml (~21oz) fluid per hour. Without detailed data on Ruth’s sweat rate, this seems like an adequate volume to replace a proportion of her expected losses and is higher than her intake at her previous race in Mallorca (~495ml/17oz per hour). Considering the windy conditions made handling difficult on the bike leg, Ruth did well to achieve a high fluid intake to replace her losses in warm conditions
      • She mentioned peeing quite a few times on the run (~5 times), which would indicate that she didn’t under hydrate and therefore she could consider dialling her fluid intake back slightly if she wanted to
      • Ruth had some sodium in her pre-made energy drink mix, but also added PH 1500 to a proportion of the water she picked up on the bike
      • This meant the relative sodium concentration of her intake was ~518mg/L. This will have replaced a good proportion of her sweat losses (Ruth falls on the low-to-moderate side of the scale in terms of sweat sodium concentration)


    Quick Carb Calculator Recommendation


    carb 30 mins before


    carb per hour during
      • Before the race, Ruth consumed a carb-rich breakfast consisting of rice and honey which was different to her typical breakfast as they didn’t have her usual rice pudding in South Africa, but this obviously didn’t cause her too much of an issue. She also sipped on some energy drink mix leading up to the start of the race to top off her fuel stores (learn more)
      • As Ruth did at IM Mallorca, she used a pre-made energy drink mix during the race, but this time the mix was smaller, containing 225g carb and mixed into 750ml/~25oz of water. She also consumed carbs from other energy drink mixes on the bike and run legs, as well as three energy gels during the marathon
      • This meant she consumed an average of ~37g/hr (including swim time). This is lower than the high numbers we have seen Ruth pushing towards previously and lower than our Quick Carb Calculator’s recommended 60-90g/hr for a race of this intensity and duration
      • Ruth’s intake was lower than she’d aimed for because she thought she had finished all of her pre-made drink mix, but when she finished the race she realised there was still around half left in her fin at the back of the bike. If she’d finished the drink mix, she would have been pushing towards ~50g/hr
      • For races of this long duration, we generally recommend keeping your bottles for hydration and your more solid sources for fueling, but it will be a case of working out what works best for you as an athlete
      • On this occasion, Ruth combined her hydration and fuel into a single source on the bike leg by relying on the fluids in her bottle, which had a knock on effect as it meant her overall carb intake was affected by the fact she didn’t finish her bottle. Clearly, this didn’t have a totally adverse effect on her race this time as she produced an awesome performance to win, but it’s something to bear in mind as there can be an added danger of consuming way too much carb, too quickly when drinking lots in hot races
      • Her GI comfort was “great all day” and she rated her energy levels at ~9 until the last 30km of the bike, when they dropped to a 7. Similarly on the run, Ruth said her energy was about a 9 after T2 then dropped to about a 6 on lap 3. This drop in energy towards the end of the bike and run could have been linked to her relatively low carb intake, with Ruth mentioning that her fueling in this particular race “could have been better”


      • Ruth rated her race satisfaction as 8 out of 10 and said “generally things went to plan, other than not drinking all the carb mix. I definitely felt like I needed more hydration in the heat and the wind - the wind felt very energy sapping and dehydrating”
      • Despite a relatively low carb intake, Ruth produced a superb performance. But, she did illude to this being her 'hardest IM' yet which may have been a result of the lower carb intake and the tough conditions. Considering she usually aims for 60-75g/hr we would recommend she looks to increase her bike and run carb intake to hit this again
      • We hope Ruth gets some well deserved rest this off-season and we’re looking forward to seeing what she achieves next year!

    Key info

    Ruth Astle



    Overall Time
    Swim Time
    Bike Time
    Run Time

    Event information

    Full distance
    IRONMAN® South Africa
    Summerstrand, South Africa
    21st November, 2021
    Swim Distance
    3.8km / 2.4mi
    Bike Distance
    180.2km / 112.0mi
    Run Distance
    42.2km / 26.2mi
    Total Distance
    226.2km / 140.6mi
    Bike Elevation
    190m / 623ft
    Run Elevation
    36m / 118ft
    Total Elevation
    226m / 741ft

    Race conditions

    Weather Conditions
    Hot and Humid
    No Rain
    Min Temp
    18°C / 64°F
    Max Temp
    20°C / 68°F
    Avg Temp
    20°C / 68°F

    Athlete feedback

    Race Satisfaction
    Hydration rating
    Energy levels
    9 until last 30km of the bike, then probably dropped to 7. Similarly on run, picked back up to a 9 then dropped to a 6 on lap 3
    Toilet stops
    Peed a lot on the run - I would estimate 5 times throughout the run
    GI comfort
    Felt great all day stomach/GI wise
    No cramping

    Ruth's full stats

     Carbohydrate (g)Sodium (mg)Fluid (ml)Caffeine (mg)Relative sodium concentration (mg/L)
    Total intake3202,8105,42540518
    Per hour373256275
    Bike and Run
    Total intake3202,8105,42540518
    Per hour393466675
    Total intake1952,6703,3750791
    Per hour405426850
    Total intake1251402,0504068
    Per hour394464113

    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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