Arc of Attrition

For a race of this duration, carb loading is extremely important as it helps to ensure maximal stored energy in the liver and muscles on race day. Sam did this successfully by eating between 8-12g of carbohydrate for each kilo of bodyweight for the 48 hours leading up to the Arc. Along with this, it was important for Sam’s strategy to consider real foods as well as sports nutrition products since it overlapped several meal times. Sam had a general outline for his fueling strategy going into the race which focused on sports energy products for most of it, although he felt incredibly strong cravings for a variety of unplanned items, especially Cola. He ended up consuming everything from minestrone soup and jelly sweets, and was even force fed rice pudding by his supportive crew (somewhat willingly), enabling him to achieve an average carb intake of ~87g per hour. It’s impressive that his self described “granite gut” could tolerate these foods while averaging around seven minutes per kilometre (~11:15/mile) for over 22 hours! Going forward, Sam will be experimenting during training sessions to optimise the format of his carb intake by testing out a variety of different fueling products.

For a race in the UK in January, it was evident that the temperature was going to be relatively low over the course of this event, so Sam wouldn’t be sweating a huge amount. Overall, Sam was able to drink an average of ~313ml (10oz) fluid per hour, with a relative sodium concentration of ~1,139 milligrams of sodium per litre (mg/32oz). We know from Sam’s Sweat Test that he loses 819mg of sodium per litre of sweat (mg/32oz), so his intake of ~1,139mg/L was likely more than was required given the temperate conditions. This might well explain the “puffiness” he experienced and his 3kg body mass gain across the race. Sam mentioned that he craved Coca Cola from around mile 21. Affectionately known as the ‘Red Ambulance’ in endurance circles, we often observe athletes who haven’t quite got their strategy dialled in turning to cola during the latter stages of races as it can provide fluid, carbohydrate and some caffeine all at once.

During extremely long events, especially when they take place throughout the night, it’s common to see athletes exceed the general recommendations of 3-6mg/kg of caffeine. On this occasion, Sam far exceeded this, consuming 20mg/kg. Sam has a high tolerance for caffeine and experienced no adverse effects during the race itself, although he reported excessive post-race sweating. High caffeine intakes combined with muscle damage have been linked to this occurrence. Going forwards, Sam is going to reduce but optimise the timing of his caffeine intake, especially overnight when he’ll be fighting his natural sleep cycle, to exploit caffeine’s 4-5 hour ‘half-life’, and benefit from the increased perceived energy associated with it.