Hydration - A key pillar of race day fuelling
Most IRONMAN triathletes understand that reducing dehydration is critical for peak endurance performance. While dehydration can reduce athletic performance by up to 30% (Walsh et al 1994), recent research indicates that even when drinking to thirst, athletes can lose over 2% bodyweight resulting in a 7% decrease in cycling power output (Adams et al 2018). As a fundamental pillar of race-day nutrition, proper hydration can also increase muscle efficiency in utilising glycogen stores (Logan-Sprenger et al 2015), enhance the body’s ability to process carbohydrates and reduce GI distress.
Hydration is a balancing act
When it comes to hydration, every athlete is different. The key is to have a plan that has been developed based on your individual requirements, tested thoroughly in training and then stick to it religiously on race-day. The aim is to achieve an optimum balance of fluids and electrolytes, while also meeting race-day energy requirements.
While water is very effective at fluid replenishment, consumed in isolation or excess it can lead to hyponatremia (Montain et al 2001). On the other hand, many isotonic sports drinks are actually higher in sugar than levels naturally in the body (Mettler et al 2006). While this provides an energy source, it comes at the expense of hydration as the high sugar concentration actually slows fluid absorption. Hypotonic electrolyte drinks are lower in sugar than the blood and have been proven to promote faster hydration compared with isotonic sports drinks (Rowlands et al 2011). Race-day energy requirements can still be met through gels, bars and other fuelling products while being separated from fluid intake where possible.
Enhancing hydration: The latest research
Recently published research indicates that consuming drinks with a unique resistant starch pre- and post-exertion can enhance the hydration effectiveness of electrolyte drinks and water by promoting better fluid uptake in the large intestine (O’Connell et al 2018).
Based on over 20 years of University medical research, the PREPD two-step hydration system was able to demonstrate significantly better hydration before, during and after exertion in elite AFL football players compared with consuming leading sports drinks only. Results included an 85% lower reduction in bodyweight overall and according to Accredited Sports Dietitian Anthony Meade, “Given that 2% dehydration in bodyweight loss leads to decreased performance, the benefits demonstrated by PREPD clearly enhances best practice hydration and is ultimately very likely to improve athletic performance.”
Hydration strategies for IRONMAN events
- Athlete sweat rates can vary from 1-3L per hour (Kovacs 2006), and sodium concentration in sweat can range between 200mg/l and 2000mg/l (Precision Hydration). We recommended athletes determine their own fluid and electrolyte losses through a sweat rate test to inform fluid consumption rates and help identify which electrolyte products can best meet individual sodium needs.
- Consume PREPD Prime 12-18 Hours before intense training sessions and PREPD Recover immediately after for better hydration allowing you to train harder and recover sooner.
Before the race
- Consume PREPD Prime the evening before race day to start properly hydrated and boost fluid absorption during exertion, which helps reduce dehydration in the later stages of the race.
- Some research also suggests there may be benefits in pre-race sodium loading to expand plasma volume (with concentrations not over 164 mmol/l Na(+) (Mora-Rodriguez 2013), when consumed 2 hours prior to exertion.
On the bike
- Stick with your hydration plan and consume electrolyte drinks consistently on the bike leg at around 250ml every 15 minutes or as established through sweat rate testing.
On the run
- Use each run-course aid station to replenish fluids and aim to consume 150ml each time or around five gulps. If needed, slow down momentarily to ensure you can drink properly.
- Consumer PREPD Recover immediately after the race to enhance rehydration in the following 24 hours for better recovery.
- Best-practice rehydration guidelines suggest athletes should aim to replace 120-150% of the weight lost in sweat within the first 6 hours of recovery (Sports Dietitians Australia).