{
  "abstract": "BackgroundCommercial spaceflight now carries civilians on short missions, yet their stress-axis physiology is poorly described. Earlier shuttle data suggest that sympathetic responses predominate after short flights and glucocorticoid responses after long ones. The neutrophil-to-lymphocyte ratio (NLR) is a low-cost readout of both.\n\nMethodsPreregistered secondary analysis of open clinical laboratory data (NASA Open Science Data Repository OSD-569 and OSD-575) from the four Inspiration4 crew members, each sampled seven times: three draws before launch, one the day after return (R+1) and three during recovery (R+45 to R+194). Log-transformed NLR was modelled with a linear mixed model with a random intercept per crew member and Kenward-Roger inference. Lymphocyte and eosinophil counts and C-reactive protein were secondary outcomes with false discovery rate correction.\n\nResultsAll 28 draws were analysed. NLR at R+1 did not differ from pre-flight (fold change 1.04; 95% CI 0.81 to 1.34; p = 0.73); two crew members increased (+25% and +46%) and two decreased (-27% and-11%). During recovery NLR was 23% lower than pre-flight (fold change 0.77; 95% CI 0.64 to 0.92; p = 0.005). No secondary outcome changed after correction; lymphocytes were 18% lower at R+1 (95% CI -35% to +4%; q = 0.31). Between-person differences explained 58% of the variance. An ordinary regression ignoring repeated measures missed the recovery effect (p = 0.08).\n\nConclusionsA 3-day orbital flight produced no consistent leukocyte stress signature one day after return. The lower NLR during recovery suggests that pre-flight values, not recovery values, deviate from the resting state, which has implications for how baselines are defined in short-duration spaceflight studies.",
  "abstract_shown": true,
  "affiliations": [
    "Instituto Mexicano del Seguro Social"
  ],
  "article_type": "PUBLISHAHEADOFPRINT",
  "arxiv": null,
  "author_total": 1,
  "authors": [
    {
      "affs": [
        0
      ],
      "name": "V. J. GODINEZ VAZQUEZ"
    }
  ],
  "bibtex": "https://research.draconitic.com/paper/8b6zh2j2yq3vr.bib",
  "cited_by": 1,
  "doi": "10.64898/2026.10.16.26365757",
  "fulltext_url": "https://www.medrxiv.org/content/10.64898/2026.10.16.26365757v1.full",
  "id": "8b6zh2j2yq3vr",
  "issns": [],
  "landing_url": "https://www.medrxiv.org/content/10.64898/2026.10.16.26365757v1",
  "language": null,
  "licence": "CC-BY",
  "licence_label": "CC BY",
  "licence_source": "article",
  "licence_url": "https://creativecommons.org/licenses/by/4.0/",
  "metadata_licence": null,
  "native_subjects": [
    [
      "medrxiv",
      "occupational and environmental health"
    ],
    [
      "openalex",
      "2737|Spaceflight effects on biology"
    ]
  ],
  "openalex": "W7222968035",
  "pdf_url": "https://www.medrxiv.org/content/10.64898/2026.10.16.26365757v1.full.pdf",
  "pmcid": null,
  "pmid": null,
  "published": "2026-10-16",
  "publisher": null,
  "ris": "https://research.draconitic.com/paper/8b6zh2j2yq3vr.ris",
  "sources": [
    {
      "first_seen": "2026-10-30T12:21:10Z",
      "native_id": "10.64898/2026.10.16.26365757",
      "source": "medrxiv",
      "url": "https://www.medrxiv.org/content/10.64898/2026.10.16.26365757v1"
    }
  ],
  "subjects": [
    {
      "field": "medicine",
      "origin": "medrxiv:occupational and environmental health",
      "subfield": "epidemiology-public-health"
    }
  ],
  "title": "Change in the neutrophil-to-lymphocyte ratio after a 3-day orbital flight: A preregistered secondary analysis of NASA open data from the Inspiration4 civilian crew",
  "title_text": "Change in the neutrophil-to-lymphocyte ratio after a 3-day orbital flight: A preregistered secondary analysis of NASA open data from the Inspiration4 civilian crew",
  "type": "preprint",
  "updated_at": "2026-10-30T12:21:10Z",
  "url": "https://research.draconitic.com/paper/8b6zh2j2yq3vr",
  "venue": "medRxiv",
  "versions": []
}