{
  "abstract": "The Muse 2 EEG headset also records forehead photoplethysmography (PPG). We tested whether its pulse intervals can replace Polar H10 RR intervals for ultra-short heart-rate variability in 28 seated recordings (60 s eyes open, then 60 s eyes closed), using fixed processing, no exclusions and eleven sensitivity analyses. Mean heart rate agreed almost perfectly (ICC [≥] 0.999; bias -0.22 and 0.00 beats min-1). SDNN agreement was good to excellent (ICC 0.86 and 0.91; bias +8.6 and +8.2 ms). RMSSD agreement was moderate (ICC 0.60): Muse exceeded Polar in at least 27 of 28 sessions (bias +19.2 and +18.5 ms; about 1.9-fold), and the ratio bias fell as RMSSD rose. Interval differences (SD 23 ms) implied about 16 ms of independent timing error per pulse, which reproduced the RMSSD bias; without ECG, sensor jitter could not be separated from variation in pulse transit time. Tracking of the eyes-closed change in ln RMSSD was not demonstrated ({rho} = 0.35, 95% CI -0.07 to 0.67; detectable {rho} [≥] 0.51). Muse 2 PPG can supply mean heart rate and, with a stated bias, SDNN; its ultra-short RMSSD is not interchangeable with Polar RMSSD and should be reported as pulse-rate variability.",
  "abstract_shown": true,
  "affiliations": [
    "Universitas Udayana"
  ],
  "article_type": "PUBLISHAHEADOFPRINT",
  "arxiv": null,
  "author_total": 3,
  "authors": [
    {
      "affs": [
        0
      ],
      "name": "I. P. A. Griadhi"
    },
    {
      "name": "I. A. A. Suadnyana"
    },
    {
      "name": "N. Wahyuni"
    }
  ],
  "bibtex": "https://research.draconitic.com/paper/9hssfwe03z8sk.bib",
  "cited_by": 0,
  "doi": "10.64898/2026.10.05.26364782",
  "fulltext_url": "https://www.medrxiv.org/content/10.64898/2026.10.05.26364782v1.full",
  "id": "9hssfwe03z8sk",
  "issns": [],
  "landing_url": "https://www.medrxiv.org/content/10.64898/2026.10.05.26364782v1",
  "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",
      "sports medicine"
    ],
    [
      "openalex",
      "2204|Non-Invasive Vital Sign Monitoring"
    ]
  ],
  "openalex": "W7220968795",
  "pdf_url": "https://www.medrxiv.org/content/10.64898/2026.10.05.26364782v1.full.pdf",
  "pmcid": null,
  "pmid": null,
  "published": "2026-10-05",
  "publisher": null,
  "ris": "https://research.draconitic.com/paper/9hssfwe03z8sk.ris",
  "sources": [
    {
      "first_seen": "2026-10-30T12:20:26Z",
      "native_id": "10.64898/2026.10.05.26364782",
      "source": "medrxiv",
      "url": "https://www.medrxiv.org/content/10.64898/2026.10.05.26364782v1"
    }
  ],
  "subjects": [
    {
      "field": "medicine",
      "origin": "medrxiv:sports medicine",
      "subfield": "general"
    }
  ],
  "title": "Muse 2 forehead photoplethysmography agrees with Polar H10 for heart rate but overestimates ultra-short RMSSD",
  "title_text": "Muse 2 forehead photoplethysmography agrees with Polar H10 for heart rate but overestimates ultra-short RMSSD",
  "type": "preprint",
  "updated_at": "2026-10-30T12:20:26Z",
  "url": "https://research.draconitic.com/paper/9hssfwe03z8sk",
  "venue": "medRxiv",
  "versions": []
}