• Alex is a lawyer by day and runner by night, competing both internationally, and for the Highgate Harriers running club in London
• With impressive personal bests over the 5km (13:55) and 10km (30:18) and Half marathon (63:28), Alex was hoping to carry this speed across to his debut marathon at London 2023
• As this was the first event Alex has ever had to think about fueling or hydrating during, he worked with the PF&H Sports Science team in advance to prepare his strategy
• Amazingly, despite his impressive running pedigree, Alex did not secure an elite start position, meaning he began the race with the 40,000 non-elite starters, of which only two beat him on the day. This meant Alex barely saw another runner for the 42.2km, and wasn’t able to run in a pack like the pros

Hydration

• Alex understood that starting endurance events dehydrated is actually a very common performance limiting issue, and so decided to try and start optimally hydrated by preloading with a PH 1500 both the night before and morning of the marathon
• This ‘preloading’ helps performance by encouraging retention of water within the blood plasma, so the cardiovascular system doesn’t have to work any harder than absolutely necessary. Alex has also found that this retention has reduced the feeling of needing to pee mid-race
• With the context of his excellent pre-hydration, combined with the mild (13°C / 55°F) and rainy weather, it wasn’t surprising to hear that Alex never felt particularly thirsty throughout this race
• This is because there was less need for the body to offload excess heat through sweating, and therefore less fluid loss needed to be replaced in order to keep him above 2% body weight loss, which is generally thought to be where performance declines start to occur
• While he only drank ~250ml (8oz) of plain water across the two and a quarter hours, we would still recommend drinking some electrolytes, in order to get sodium on board while running
• One of the main reasons for this is the key role that sodium plays in assisting with carbohydrate absorption, via ‘glucose sodium cotransporters’
• Happily, on the day Alex experienced no cramping and rated his hydration strategy a strong 7 (out of 10)

Fueling

Conclusions

• Alex was satisfied to run a 2:15:01 in his debut marathon, and beat all but two other people from the mass start pen to the finish line. He’s also confident that he’ll be able to beat this time when he lines up for the Berlin Marathon a few months after this race
• He did very well to average ~67g of carb per hour in the first race he’s ever had to eat and drink during, rating his gastrointestinal comfort at an 8 (out of 10), only getting some discomfort when swallowing some air with his water
• Looking forwards Alex will be able to optimise his use of caffeine, and continue gut training so he is happy tolerating additional carb towards the end of a marathon