{
  "abstract": "Sodium ingestion may support fluid balance and endurance performance in the heat, but most previous studies have used sodium-loading, hyperhydration, or carbohydrate-electrolyte protocols. This study examined the effects of a high-sodium, carbohydrate-free multi-electrolyte supplement (HSES) on 15 km treadmill time-trial performance and physiological responses in trained male runners under warm-humid conditions. In a randomized, single-blind, counterbalanced crossover design, ten trained male runners (V̇O₂max: 57.3 ± 8.1 mL·kg⁻¹·min⁻¹) completed two 15 km treadmill time trials at 26.7 °C and 60% relative humidity. Participants received HSES or a flavor-matched placebo (PLA) 30 min before exercise and every 15 min of running time. Repeated-measures analysis of cumulative completion time showed a significant main effect of condition (p = 0.034) and a significant condition × distance interaction (p = 0.023). Segment pace also showed a significant condition × segment interaction (p = 0.001); participants ran faster during HSES over the opening 0-5 km (p < 0.001), pace did not differ during 5-10 km (p = 0.091), and participants ran faster during PLA over the final 10-15 km (p = 0.032). Mean final 15 km completion time was 68.76 ± 12.28 min during HSES and 70.18 ± 13.33 min during PLA, a mean difference of 1.42 min (~2.0%). However, the direct paired comparison of final completion time did not reach statistical significance (HSES - PLA: -1.42 min; 95% CI, -3.60 to 0.77 min; p = 0.176; Cohen's dz = -0.46). No significant between-condition differences were observed in measured hydration-related, cardiovascular, metabolic, or perceptual outcomes. Estimated core temperature was higher during HSES at 15 km and 10 min post-exercise. Pacing differed between conditions during the 15 km time trial, with a faster opening 5 km during HSES and a faster final 5 km during PLA. Final 15 km completion time was approximately 2.0% faster during HSES, although the difference was not statistically significant.",
  "abstract_shown": true,
  "affiliations": [
    "Department of Exercise Science, Grove City College, Grove City, PA 16127, USA.",
    "Emeritus Faculty of Health Sciences, University of Cape Town, Cape Town 7925, South Africa."
  ],
  "article_type": "research article",
  "arxiv": null,
  "author_total": 7,
  "authors": [
    {
      "affs": [
        0
      ],
      "name": "Philip Prins",
      "orcid": "0000-0002-1761-1129"
    },
    {
      "affs": [
        0
      ],
      "name": "Jeffrey D Buxton"
    },
    {
      "affs": [
        0
      ],
      "name": "Abigail Helsel"
    },
    {
      "affs": [
        0
      ],
      "name": "Sarah Bonnett"
    },
    {
      "affs": [
        0
      ],
      "name": "Luke DeMember"
    },
    {
      "affs": [
        0
      ],
      "name": "Jackson Timko"
    },
    {
      "affs": [
        1
      ],
      "name": "Timothy Noakes"
    }
  ],
  "bibtex": "https://research.draconitic.com/paper/6cmexry6s0tcj.bib",
  "cited_by": 0,
  "doi": "10.3390/sports14100435",
  "fulltext_url": "https://europepmc.org/articles/PMC13709417",
  "id": "6cmexry6s0tcj",
  "issns": [
    "2075-4663"
  ],
  "landing_url": "https://europepmc.org/article/MED/42931572",
  "language": "eng",
  "licence": "CC-BY",
  "licence_label": "CC BY",
  "licence_source": "article",
  "licence_url": "https://creativecommons.org/licenses/by/4.0/",
  "metadata_licence": null,
  "native_subjects": [
    [
      "openalex",
      "2737|Thermoregulation and physiological responses"
    ]
  ],
  "openalex": "W7220848412",
  "pdf_url": "https://europepmc.org/articles/PMC13709417?pdf=render",
  "pmcid": "PMC13709417",
  "pmid": "42931572",
  "published": "2026-10-07",
  "publisher": null,
  "ris": "https://research.draconitic.com/paper/6cmexry6s0tcj.ris",
  "sources": [
    {
      "first_seen": "2026-10-30T12:22:01Z",
      "native_id": "MED:42931572",
      "source": "europepmc",
      "url": "https://europepmc.org/article/MED/42931572"
    }
  ],
  "subjects": [
    {
      "field": "medicine",
      "origin": "openalex:2737|Thermoregulation and physiological responses",
      "subfield": "physiology"
    }
  ],
  "title": "Effects of a High-Sodium, Carbohydrate-Free Multi-Electrolyte Supplement on 15 km Treadmill Time-Trial Performance in Warm and Humid Conditions: A Randomized, Single-Blind, Placebo-Controlled Crossover Trial.",
  "title_text": "Effects of a High-Sodium, Carbohydrate-Free Multi-Electrolyte Supplement on 15 km Treadmill Time-Trial Performance in Warm and Humid Conditions: A Randomized, Single-Blind, Placebo-Controlled Crossover Trial.",
  "type": "peer-reviewed",
  "updated_at": "2026-10-30T12:22:01Z",
  "url": "https://research.draconitic.com/paper/6cmexry6s0tcj",
  "venue": "Sports (Basel, Switzerland)",
  "versions": []
}