REF-230 · Bell SK & Spriet LL, 2025 · Journal of Strength and Conditioning Research, · Paper · PubMed
Rehydration After Exercise-Induced Fluid Losses: Comparing Flavored Water, Coconut Water, and Carbohydrate-Electrolyte Sports Beverage
Participants
n=8 recreational athletes (7 men, 1 woman; 22.3 ± 0.4 yr; VO2max 48.2 ± 2.2 mL/kg/min)
Protocol
Cycling at 70% VO2max for 60 min until dehydrated by 1.36 ± 0.1% of body mass (1.07 ± 0.1 kg)
Three separate trials: flavored water (FW), coconut water (CW) or carbohydrate-electrolyte sports drink (CES), each at 150% of body-mass lost
Hydration status from body mass and urine volume; saltiness, thirst and nausea on a 5-point Fluid Sensation Scale
Key Results
| Beverage | Total urine output after rehydration | Fluid status post-rehydration |
|---|---|---|
| Flavored water (FW) | 530 ± 119.2 mL (greater than CW and CES, p<0.05) | not different from the others (p>0.05) |
| Coconut water (CW) | 170 ± 35.8 mL | greatest fluid volume retained, but not significantly |
| Sports drink (CES) | 170 ± 35.8 mL | not different |
Perceived thirst was greater for FW and CES at 0 min of rehydration (p<0.05); saltiness and nausea did not differ.
Key Findings
Coconut water retained fluid as well as the commercial electrolyte sports drink, despite a lower sodium concentration (potassium-rich)
Flavored water produced about three times the urine output of CW or CES — yet fluid status after rehydration was not statistically different between the three drinks
Palatability (saltiness, nausea) comparable; thirst at the start of rehydration was lower with coconut water
Practical Application
In 8 recreational athletes dehydrated 1.36% by 60 min of cycling and given 150% of the loss to drink, coconut water and a carbohydrate-electrolyte sports drink produced the same urine output (170 mL) versus 530 mL with flavored water; fluid status after rehydration did not differ significantly between the three. Coconut water is a legitimate natural rehydration option after training, on par with a sports drink for retention and palatability.
Plain flavored water is not useless — the final fluid status was statistically similar — but you pass more of it as urine, so with an electrolyte-free drink expect to need more volume for the same net retention.
Not from this paper; the base's own practice: during exercise still favour a sodium-containing drink (see REF-224 for during-exercise hydration); the mild dehydration here (1.36%) is a typical training day, not a hot race.
Limitations
From the design as the abstract reports it: randomized single-blind crossover in only 8 recreational athletes (7 men, 1 woman).
Mild dehydration (1.36% of body mass after 60 min at 70% VO2max); larger fluid deficits were not tested.
Outcomes were body mass, urine volume and perceptual ratings; no subsequent exercise performance was measured.
The greater fluid retention with coconut water was not statistically significant (p > 0.05).
How this entry was checked and changed
Why this level
regraded 2026-09-27 from B+: crossover, n=8 (rubric: crossover <15)
Content correction 2026-09-27
Journal line "Journal of the International Society of Sports Nutrition, 22(1)" -> the DOI is J Strength Cond Res 40(4): 431-438, 2026.
"Flavored water: worst retention / poor for rehydration", "avoid plain water for serious rehydration" -> the abstract says fluid status post-rehydration was not significantly different between beverages; only urine output differed. Nuanced accordingly.
"Contains some carbohydrate", "500 mL coconut water + snack" -> not in the abstract; removed. Level B+ -> B (crossover n=8); Tier 2-3 -> 1-2 (recreational athletes, VO2max 48). Added the abstract's dehydration protocol and thirst result.
2026-09-28: added Limitations from the abstract (Europe PMC PMID 41359932).