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.
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.
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.”
Before the race
On the bike
On the run