IAU 24H World Championships

Before the race, Sophie set her fueling target at ~75g of carb per hour, which would have been a ~21% jump from what we saw her do at the 24h European Championships in 2022. Unfortunately some hotel food related gastrointestinal issues during the first half of the run derailed Sophie’s plan. Considering this, it was impressive to see her still tolerate ~58g per hour and it appears she struck the balance between real food and sports fuel products appropriately. Incorporating real food will have helped Sophie to not feel too hungry during the run, whilst giving her something novel to look forward to, and importantly assisted in avoiding flavour fatigue. Sophie’s suggestion to make her crew force her to eat during the latter stages may feel quite abrasive, however we can see a significant drop off in her intake across the hours, from taking in as much as 90g carb during the fourteenth hour, to just 30g for the last three hours in a row. In addition to adopting a stricter approach, adopting a more consistent ‘little and often’ approach may help her maintain her appetite better.

The temperature in Taipei only reached ~21ºC during this event, but the extreme humidity (~90% on average) meant that Sophie’s sweat couldn’t evaporate as efficiently as it would in drier climates, meaning she was more prone to overheating. This likely explains her request for an ice bandana during what would typically be the coolest hours of the race. As someone with a fairly low sweat rate, Sophie did a good job of replacing fluid with up to 750ml per hour during the hottest periods when her losses were higher, and ended up achieving a relative sodium concentration which closely resembled her sweat losses by using PH 1500 (Tablets) and some salty foods.

Sophie’s caffeine intake was above the general scientific recommendations during this event. However, considering the specifics of a 24h race, where she had to stave off sleep entirely, it would have been a surprise to see her take much less. Typically, ultra runners try to abstain from caffeine so they have a noticeable boost when they need it. On this occasion, Sophie may have taken this slightly too far, as during hour fourteen of the race, at 23:00, Sophie’s crew noted she was “begging for caffeine” and she also saw a small dip in her lap times. This could well have been avoided, as the associated benefits of caffeine are reducing perceived exertion and increasing focus.