• Paul is an extremely experienced swimming coach and marathon swimmer, who has previously crossed the English Channel and won the 48km Manhattan Island Marathon Swim in 2013
• Paul took on the Rottnest Swim for the 12th time in 2023 and, having tried to break 5 hours for the 19.7km distance since he was 31, he was incredibly happy to cross the finish line in 4:55:46 at 44 years old. For the first time ever, he even felt like he could have gone harder, which he partly attributed to his pacing and partly to nailing his fueling better than during any previous attempt

Hydration

• We know from experience that getting fluids on board during long swims can be difficult due to the practicalities of stopping to drink, so it's important to make sure you start hydrated. Paul sensibly made sure he was optimally hydrated by preloading with a PH 1500 tablet in 500ml (16oz) of water before the race started
• Paul drank a total of ~1.75L (62oz) of fluid while swimming, which averaged out to ~356ml (13oz) per hour. The one thing Paul would have changed about this race was drinking a little bit more. However, he was held back by some bladder discomfort, and being unable to pee in his very tight swim skin suit
• Because Paul weighed himself before and after the race, we’re able to work out his hourly sweat rate. With a loss on the scales of 1.8kg in 5 hours, and an approximate weight of the drinks he consumed totalling 1.75kg, his total losses across the race were roughly 3.55L (125oz)
• This works out at an hourly sweat rate of ~720ml (25oz) and does suggest that a higher fluid intake on the day would have been appropriate. For context, if he hadn’t drunk anything, he would have lost ~3.5kg (123oz) in sweat, this is equivalent to ~4.5% of his body weight
• This is important to know, as the scientific literature generally suggests that physical performance may start to decline in individuals after around 2-4% dehydration, and so could have caused some issues. Although, having done this successfully for a long time, it’s likely that Paul’s tolerance to moderate dehydration is more robust than others
• Paul sensibly added electrolytes to his drinks in the form of PF 60 Drink Mix. This resulted in him taking on ~714mg of sodium per litre (32oz) of fluid that he drank. As Paul has previously had a Sweat Test he knows that he loses 819mg/L (mg/32oz), and so can be confident that on this occasion he replaced a good proportion of his losses
• Having ensured that he mitigated against the onset of muscle cramping due to electrolyte related causes, Paul was very pleased to report no cramps whatsoever throughout the race. This is especially pleasing as it’s normally something he struggles with in his quadriceps

Fueling

Conclusions

• In a race field containing several Olympians, Paul was incredibly satisfied with his new personal best time and the achievement of finishing in under 5 hours. He said he ‘felt very well supported by his fuel & hydration strategy’, which gave him plenty of energy for the race and confidence going into the next one
• Going forwards, Paul may look to increase his fluid intake slightly in order to avoid accumulating as much dehydration related to body weight loss, as well as position himself in a way where he will be able to pee comfortably if needed