{
  "abstract": "With ascent to high altitude (HA), increased ventilation reduces the pressure of PaCO₂ (i.e., hypocapnia), resulting in respiratory alkalosis. A subsequent renal compensation is mediated through reductions in [HCO₃ ⁻]a, partly-correcting pHa. High inter-individual variability exists in ventilation, blood oxygenation, and acid-base responses with ascent to HA, but potential sex differences have not been well-characterized. We recruited 38 lowland participants (20 M; 18 F) before and after rapid ascent to and residence at 3500 m over 10 days in La Paz, Bolivia. We performed radial arterial blood draws to assess blood oxygenation and acid-base variables before (1100 m), and following ascent to 3500 m both early HA (E-HA; D2/3) and late HA (L-HA; D9/10). With E-HA, all participants had higher calculated V̇ A, and lower PaO₂ and SaO₂ (p < 0.0001), with subsequent increases in V˙ A, [Hb] and CaO₂ L-HA (p = 0.0056; p = 0.0003; p = 0.0013). Although females had higher V˙ A and PaO₂ than males E-HA (p < 0.0001; p = 0.0143), males had higher [Hb] and CaO₂ at 1100 m, at both E-HA (p = 0.0008; p = 0.0085) and L-HA (p = 0.0007; p = 0.0045). E-HA, all participants had lower PaCO₂ and [HCO₃ ⁻]a, and higher pHa than 1100 m (p < 0.0001; p = 0.0004, p < 0.0001), suggesting respiratory alkalosis and partial renal compensation. L-HA, PaCO₂ and [HCO₃ ⁻]a were further reduced (p = 0.0062; p = 0.0202), with pHa only partly-compensated (p = 0.4306). E-HA, PaCO₂, [HCO₃ ⁻]a and pHa were significantly lower in females (p < 0.0001; p < 0.0001; p = 0.0457), suggesting more complete renal compensation. However, these sex-differences were not apparent at L-HA (p > 0.5341). This is the first clear demonstration of differential ventilatory, oxygenation and acid-base compensation between sexes with rapid ascent to HA.",
  "abstract_shown": true,
  "affiliations": [
    "Department of Biology, Faculty of Science and Technology Mount Royal University Calgary Alberta Canada.",
    "Department of Emergency Medicine, Cumming School of Medicine University of Calgary Calgary Alberta Canada.",
    "Mineral Springs Hospital Banff Alberta Canada.",
    "High Altitude Pulmonary and Pathology Institute (HAPPI-IPPA) La Paz Bolivia.",
    "Department of Physiology and Pharmacology, Cumming School of Medicine University of Calgary Calgary Alberta Canada."
  ],
  "article_type": "research article",
  "arxiv": null,
  "author_total": 9,
  "authors": [
    {
      "affs": [
        0
      ],
      "name": "Nicole V Bushfield",
      "orcid": "0009-0009-3865-3000"
    },
    {
      "affs": [
        0
      ],
      "name": "Benjamin W L MacKenzie",
      "orcid": "0009-0004-4097-7382"
    },
    {
      "affs": [
        0
      ],
      "name": "Nicole A Johnson"
    },
    {
      "affs": [
        0
      ],
      "name": "Rodion Isakovich"
    },
    {
      "affs": [
        1,
        2
      ],
      "name": "Jamie L Keess"
    },
    {
      "affs": [
        0
      ],
      "name": "Nicholas D J Strzalkowski",
      "orcid": "0000-0003-4998-2300"
    },
    {
      "affs": [
        3
      ],
      "name": "Gustavo Zubieta-Calleja",
      "orcid": "0000-0002-4283-6514"
    },
    {
      "affs": [
        4
      ],
      "name": "Richard J A Wilson",
      "orcid": "0000-0001-9942-4775"
    },
    {
      "affs": [
        0,
        4
      ],
      "name": "Trevor A Day",
      "orcid": "0000-0001-7102-4235"
    }
  ],
  "bibtex": "https://research.draconitic.com/paper/er06mz4pcxt1h.bib",
  "cited_by": 0,
  "doi": "10.1002/cph4.70279",
  "fulltext_url": "https://europepmc.org/articles/PMC13695047",
  "id": "er06mz4pcxt1h",
  "issns": [
    "2040-4603"
  ],
  "landing_url": "https://europepmc.org/article/MED/42926907",
  "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",
      "1311|High Altitude and Hypoxia"
    ]
  ],
  "openalex": "W7223464353",
  "pdf_url": "https://europepmc.org/articles/PMC13695047?pdf=render",
  "pmcid": "PMC13695047",
  "pmid": "42926907",
  "published": "2026-10-24",
  "publisher": null,
  "ris": "https://research.draconitic.com/paper/er06mz4pcxt1h.ris",
  "sources": [
    {
      "first_seen": "2026-10-30T12:21:18Z",
      "native_id": "MED:42926907",
      "source": "europepmc",
      "url": "https://europepmc.org/article/MED/42926907"
    }
  ],
  "subjects": [
    {
      "field": "biology",
      "origin": "openalex:1311|High Altitude and Hypoxia",
      "subfield": "genetics-genomics"
    }
  ],
  "title": "Daytime Ventilatory and Blood Acid-Base Responses During Ascent to 3500 m Are Larger and More Rapid in Females Than Males.",
  "title_text": "Daytime Ventilatory and Blood Acid-Base Responses During Ascent to 3500 m Are Larger and More Rapid in Females Than Males.",
  "type": "peer-reviewed",
  "updated_at": "2026-10-30T12:21:18Z",
  "url": "https://research.draconitic.com/paper/er06mz4pcxt1h",
  "venue": "Comprehensive physiology",
  "versions": []
}