Efficacy of Ingesting an Oral Rehydration Solution after Exercise on Fluid Balance and Endurance Performance.

Priscilla Weiping Fan,Stephen F Burns,Jason Kai Wei Lee

doi:10.3390/nu12123826

Priscilla Weiping Fan, Stephen F Burns + Show 1 more

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https://doi.org/10.3390/nu12123826

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Abstract

This study investigated the efficacy of ingesting an oral rehydration solution (DD) that has a high electrolyte concentration after exercise on fluid balance and cycling performance in comparison with a sports drink (SD) and water (WA). Nine healthy males aged 24 ± 2 years (mean ± SD), with peak oxygen uptake (VO2 peak) 55 ± 6 mL·kg−1·min−1 completed three experimental trials in a randomised manner ingesting WA, SD (carbohydrates: 62 g·L−1, sodium: 31 ± 3 mmol·L−1) or DD (carbohydrates: 33 g·L−1, sodium: 60 ± 3 mmol·L−1). On all trials, fluid was ingested during 75 min cycling at 65% VO2 peak (temperature: 30.4 ± 0.3 °C, relative humidity: 76 ± 1%, simulated wind speed: 8.0 ± 0.6 m·s−1) and during 2 h of recovery (temperature: 23.0 ± 1.0 °C, relative humidity: 67 ± 2%), with the total volume equivalent to 150% of sweat loss during the ride. A 45 min pre-load cycling time trial at a 65% VO2 peak followed by a 20 km time trial was conducted after a further 3 h of recovery. Fluid retention was higher with DD (30 ± 15%) than WA (−4 ± 19%; p < 0.001) and SD (10 ± 15%; p = 0.002). Mean ratings of palatability were similar among drinks (WA: 4.25 ± 2.60; SD: 5.61 ± 1.79; DD: 5.40 ± 1.58; p = 0.33). Although time trial performance was similar across all three trials (WA: 2365 ± 321 s; SD: 2252 ± 174 s; DD: 2268 ± 184 s; p = 0.65), the completion time was faster in eight participants with SD and seven participants with DD than with WA. Comparing SD with DD, completion time was reduced in five participants and increased in four participants. DD was more effective at restoring the fluid deficit during recovery from exercise than SD and WA without compromising the drink’s palatability with increased sodium concentration. Most individuals demonstrated better endurance exercise time trial performance with DD and SD than with WA.

Highlights

The debilitating effects of exercise-induced dehydration on exercise performance are well documented [1,2]
Treatments were administered in a crossover manner, with both researchers and volunteers blinded to the provision of the sports drink (SD) and DD i.e., the participants were informed that the aim of this study was to investigate different rehydration solutions during exercise and recovery on the subsequent pre-load time trial performance
One participant experienced difficulty in ingesting a volume equivalent to 150% of his fluid lost in the first experimental trial and was provided with a total volume of 120% of fluid lost in all experimental trials

Summary

Introduction

The debilitating effects of exercise-induced dehydration on exercise performance are well documented [1,2]. Nutrients 2020, 12, 3826 largely resulting from excessive fluid intake beyond the capacity for fluid excretion and/or the lack of available solution to replace the sodium lost during exercise [3,4]. Commercial carbohydrate–electrolyte sports drinks are formulated to replace the fluid and electrolytes lost through sweat, promote voluntary fluid consumption, and improve net water absorption [5]. Several studies have investigated the effects of ingesting commercially available sports drinks on the restoration of fluid balance after exercise-induced fluid deficits and found that they were generally more effective in rehydration than water or other placebo solutions [6,7,8] as a lower volume of urine was produced [9]. Apart from urine volume, the effects of sports drinks on key thermal parameters such as core temperature (Tc ) and skin temperature (Tsk )

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