• With a shortened swim from 3800m to just 900m, then hitting a speed bump which ejected some of her nutrition off her bike, it’s fair to say Fenella’s race didn’t start as planned at all. Given these set-backs early on, Fenella did phenomenally well to stay composed and adapt both her race tactics and her fuel and hydration plan on-the-go
• The end result was her stamping her ticket to the 2023 IM World Championships in Hawaii with her second place at IM South Africa. It’s also noteworthy that she ran a really solid marathon off the back of this, clocking 3:06:05, which is nearly 10 minutes quicker than her last IM marathon at the World Champs in Kona in 2022

Hydration

• The weather on race day was typically blustery with storms expected, hence the shortened swim. With storms often comes periods of high humidity, which can cause hydration related issues as athletes’ sweat isn’t as effective at cooling them as in lower humidity
• Fenella had prepared for this, and began the race having preloaded her sodium levels with PH 1500, enhancing her blood plasma volume and ensuring she started optimally hydrated . Fenella also has quite salty sweat, losing 1,331mg of sodium in each litre (32oz), highlighting the importance of preloading and an appropriate plan when racing in the heat
• After just 5km of the bike ride, she hit a speed bump that ejected two high-carb bottles from her rear bottle cages. These contained ~650ml (20oz) plain water, with a PF 90 Gel squeezed into each, so she was 180g of carb and ~1.35L of water down on her plan before the race had really got going
• Fenella’s average fluid intake was ~660ml (19oz) per hour, which was slightly lower than initially planned. Whilst she did her best to pick up some sports drink (~710ml/23oz) from the aid stations, which replaced some of the calories and fluids she’d dropped, her total fluid intake was still below what she’d hoped to consume
• Despite the lower fluid intake, she still consumed her pre-planned 18 Electrolyte Capsules, which meant the relative sodium concentration of her drinks was slightly higher than planned at just under 1,600mg per litre (mg/32oz)
• In an ideal world, Fenella would have reduced her sodium intake, or increased the amount of fluid picked up from aid stations to keep the concentration of her drinks more in line with her sweat losses. But, she did pee twice during the ride, which suggests she didn’t experience the increased fluid retention and GI risks sometimes associated with too much sodium consumption relative to fluid
• On the run, Fenella drank two PF&H Soft Flasks filled with PH 1500 to get a solid electrolyte intake, and topped this up by swallowing nine Electrolyte Capsules, and grabbing cups of aid station sports drink
• During the run she averaged a similar fluid intake of ~677ml (23oz) per hour, but with a relative sodium concentration of ~1,800mg/L (mg/32oz). This very salty concentration on average would likely explain her feeling of thirst after the race
• Whilst her total electrolyte losses were likely higher than usual due to the high temperatures and humidity, Fenella might look to reduce this concentration in future races to be more reflective of her sweat sodium concentration, possibly by reducing the number of Electrolyte Capsules or picking up a few more cups of plain water

Fueling

Conclusions

• In all, Fenella did well in an adverse situation to adapt her hydration and fuel plan on-the-fly, and still manage to maintain a high level of performance whilst doing so
• This second place booked her ticket to the big island of Hawaii for the 2023 IM World Champs, which was one of her primary aims of racing in South Africa, kudos Fenella!