Impact of Nuun Electrolyte Tablets on Fluid Balance in Active Men and Women.
Level 2 - randomized trial
Individual randomized crossover trial in healthy humans.
PubMed 33023276 · doi:10.3390/nu12103030
What was done
Eighteen exercise-trained adults (8 men, mean age 25.9 years; 10 women, mean age 28.2 years) in a fasted, euhydrated resting state completed three experimental sessions separated by approximately one week in randomized order. Participants ingested 1 L of fluid over 30 minutes consisting of water alone, water with single-strength Nuun electrolyte tablets, or water with double-strength Nuun tablets. Urine was collected at 0, 1, 2, 3, and 4 hours post-ingestion to determine fluid balance and the beverage hydration index (BHI). Heart rate, blood pressure, and pre- to post-trial body weight were also measured.
What was found
Neither heart rate nor blood pressure differed across conditions. Both single- and double-strength Nuun solutions resulted in lower urine output and significantly more favorable fluid balance compared to water starting at 2 hours and continuing through 4 hours (p < 0.05). Body weight loss was 0.38 kg for single-dose Nuun (p = 0.02 vs. water) and 0.43 kg for double-dose Nuun (p = 0.08 vs. water), compared to 0.57 kg for plain water. BHI was significantly higher for single-dose Nuun compared to water at 2 hours (p = 0.05) and 4 hours (p = 0.02). Doubling tablet strength provided no additional retention benefit at rest.
Why it matters
Electrolyte tablet supplementation improves resting fluid retention over a 4-hour period relative to plain water in healthy adults. It also demonstrates that increasing electrolyte concentration beyond standard single-strength formulation yields no added hydration benefit in a resting state.
Limits
The study had a small sample size (n = 18). Testing was conducted exclusively at rest in fasted, already-euhydrated subjects, meaning results cannot be directly generalized to exercise, thermal stress, or active rehydration following sweat-induced dehydration.
Cited by
- supports Drinking mineralized liquid, such as electrolyte water or salted tea, causes less frequent urination than drinking plain, unmineralized water.