Does a high-sodium, carbohydrate-free electrolyte drink affect 15-km running performance in trained men in warm and humid conditions?
| ISRCTN | ISRCTN39215157 |
|---|---|
| DOI | https://doi.org/10.1186/ISRCTN39215157 |
| Sponsor | Grove City College |
| Funders | Grove City College, Drink LMNT, Inc. |
- Submission date
- 23/09/2026
- Registration date
- 24/09/2026
- Last edited
- 24/09/2026
- Recruitment status
- No longer recruiting
- Overall study status
- Completed
- Condition category
- Other
Prospectively registered
Protocol
Statistical analysis plan
Results
Individual participant data
Record updated in last year
Plain English summary of protocol
Not provided at time of registration
Contact information
Dr Philip Prins
Public, Scientific, Principal investigator
Public, Scientific, Principal investigator
Department of Exercise Science, Grove City College, 100 Campus Drive
Grove City
16127
United States of America
 ORCID ID |
0000-0002-1761-1129 |
|---|---|
| Phone | +1 (0)724 458 3863 |
| prinspj@gcc.edu |
Study information
| Primary study design | Interventional |
|---|---|
| Allocation | Randomized controlled trial |
| Masking | Blinded (masking used) |
| Control | Placebo |
| Assignment | Crossover |
| Purpose | Exercise performance |
| Scientific title | Effects of a high-sodium, carbohydrate-free multi-electrolyte supplement versus placebo on 15-km treadmill time-trial performance in trained male runners exercising in warm and humid conditions: a randomized, single-blind, counterbalanced crossover trial |
| Study objectives | To determine the effects of a high-sodium, carbohydrate-free multi-electrolyte supplement compared with placebo on 15-km treadmill time-trial performance and physiological responses in trained male runners exercising in warm and humid conditions. |
| Ethics approval(s) |
Approved 15/01/2026, Grove City College Institutional Review Board (100 Campus Drive, Grove City, 16127, United States of America; +1 (0)724 458 3374; irb@gcc.edu), ref: 128-2025 |
| Health condition(s) or problem(s) studied | Endurance exercise performance and physiological responses during running in warm and humid conditions |
| Intervention | In a randomized, single-blind, counterbalanced crossover design, participants completed two 15-km treadmill time trials separated by a 7-day washout period. Treatment order was counterbalanced across participants using an alternating sequence. Thirty minutes before each trial, participants consumed either 500 ml of a high-sodium multi-electrolyte beverage containing 1000 mg sodium, 200 mg potassium, and 60 mg magnesium, or a flavor-matched placebo containing no added electrolytes. During exercise, participants consumed 250 ml of the assigned beverage every 15 min of accumulated running time until completion. Trials were performed at 26.7°C and 60% relative humidity. |
| Intervention type | Supplement |
| Primary outcome measure(s) |
|
| Key secondary outcome measure(s) | |
| Completion date | 14/04/2026 |
Eligibility
| Participant type(s) | |
|---|---|
| Age group | Adult |
| Lower age limit | 18 Years |
| Upper age limit | 50 Years |
| Sex | Male |
| Target sample size at registration | 10 |
| Total final enrolment | 10 |
| Key inclusion criteria | 1. Male 2. 18–50 years of age 3. Running ≥40 km/week 4. Trained for or completed a 10-km run within the previous 3 months 5. 10-km completion time <60 min 6. ≥2 years of distance-running experience 7. VO₂max ≥50 mL·kg⁻¹·min⁻¹ 8. Habitual mixed diet and not following a carbohydrate-restricted or other specialized dietary pattern |
| Key exclusion criteria | 1. History of smoking 2. Known metabolic, cardiovascular, or respiratory disease, including diabetes or chronic electrolyte imbalance 3. Orthopedic, neurological, or musculoskeletal condition contraindicating exercise testing; history of exertional heat stroke, recurrent heat exhaustion, or unexplained exertional syncope or heat intolerance 4. History of exercise-associated hyponatremia, syndrome of inappropriate antidiuretic hormone secretion, chronic kidney disease, heart failure, liver failure, or known salt-wasting disorders |
| Date of first enrolment | 12/02/2026 |
| Date of final enrolment | 24/03/2026 |
Locations
Countries of recruitment
- United States of America
Study participating centres
Results and Publications
| Individual participant data (IPD) Intention to share | No |
|---|
Editorial Notes
24/09/2026: Study's existence confirmed by the Grove City College Institutional Review Board.
