A new study published in Nutrients investigated the efficacy of ingesting an oral rehydration solution (ORS) that has a high electrolyte concentration after exercise on fluid balance and cycling performance in comparison with a sports drink (SD) and water. 

The present study included nine healthy males aged 24 ± 2 years, with peak oxygen uptake (VO₂ peak) 55 ± 6 mL•kg−¹•min−¹. The participants completed three experimental trials in a randomized manner ingesting water, SD (carbohydrates: 62 g•L−1, sodium: 31 ± 3 mmol•L−1) or ORS (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 and during 2 hours of recovery—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 hour of recovery. 

The findings showed that fluid retention was higher with ORS than with water and SD. While the mean ratings of palatability were similar among drinks. Though the time trial performance was similar across all three trials, the completion time was faster in participants with SD and ORS than with water. Meanwhile, ORS was more effective at restoring the fluid deficit during recovery from exercise than SD and water, without compromising the drink’s palatability. Moreover, most individuals demonstrated better endurance exercise time trial performance with ORS and SD than with water.

Hence, ORS represents a potential rehydration beverage that they could turn to help maintain better fluid balance for individuals who exercised in the heat and performed multiple exercise sessions.

Source: Nutrients. 2020 Dec; 12(12): 3826. Published online 2020 Dec 15. doi: 10.3390/nu12123826