Evidence map›Paper›PMID 40431957›Full record

ArticleSensors (Basel, Switzerland)2025

Biostrap Kairos Wristband Versus Electrocardiography for Resting Heart Rate Variability Assessment.

Andrew A Flatt, Ann Claire E Blalock, Allison N Wade, Bryan L Riemann

Abstract read
PubMed Full text at PMC Publisher
In one paragraph

Article in Sensors (Basel, Switzerland), 2025. The graph could read no effect estimate from its abstract, so it casts no vote on the map. Cited by 2 papers, 1 of them a synthesis that pooled it.

0numbers the graph read from it
0cells of the map it votes in
2citing papers in PubMed, 1 pooled it
–field-weighted citation impact
1 · What the graph read from it

What it found

Each row is one number read from the abstract, on the scale the paper reported it, with its interval. Left of the dashed line favours the treatment, right favours the comparator. Under each row is the sentence it came from. New to these charts? A ten-minute tutorial.

The abstract states no effect estimate the extractor could read, or names no intervention and outcome on the map, so this paper lights no cell and moves no belief. It is still indexed, cited and linked below.

2 · The registry

The trial behind it

Trials whose registry record cites this paper, or whose number appears in the abstract. A trial that started after this paper was published is citing it as background, not reporting it.

Neither the registry nor the abstract names a trial number. If this is a trial report, that itself is worth knowing.

3 · Its place in the literature

Who cites it

2 citing papers in PubMed, 1 synthesis or guideline pooled it.

  1. Pooled it
  2. Between-visit reproducibility of cerebrovascular and cardiovascular reactivity during the cold pressor test.American journal of physiology. Heart and circulatory physiology · 2026
    Article
4 · The record

Corrections and comments

PubMed lists nothing against this paper. Absence here is not a guarantee, only a check that was made.

5 · Who and what money

Authors and funding

4 authors.

Andrew A FlattBiodynamics and Human Performance Center, Department of Health Sciences and Kinesiology, Georgia Southern University, Armstrong Campus, 11935 Abercorn St., Savannah, GA 31419, USA.ORCID 0000-0003-2998-8537
Ann Claire E BlalockBiodynamics and Human Performance Center, Department of Health Sciences and Kinesiology, Georgia Southern University, Armstrong Campus, 11935 Abercorn St., Savannah, GA 31419, USA.ORCID 0009-0007-8486-6301
Allison N WadeBiodynamics and Human Performance Center, Department of Health Sciences and Kinesiology, Georgia Southern University, Armstrong Campus, 11935 Abercorn St., Savannah, GA 31419, USA.
Bryan L RiemannBiodynamics and Human Performance Center, Department of Health Sciences and Kinesiology, Georgia Southern University, Armstrong Campus, 11935 Abercorn St., Savannah, GA 31419, USA.ORCID 0000-0003-1850-0372

Funding

No grant is acknowledged in the PubMed record.

6 · The paper itself

Abstract

The Kairos wristband offers on-demand heart rate variability (HRV) assessment through its "Spot Check" feature, enabling standardized recordings for clinical, research, or self-tracking purposes, but its validity is untested. Therefore, we compared the Kairos wristband to electrocardiography (ECG) for resting HRV assessment in young adults, and investigated the influence of skin pigmentation (M-index) on measurement accuracy. Simultaneous 3 min Kairos and ECG samples were obtained in the supine (n = 32) and seated (n = 30) position. Comparisons included resting heart rate (RHR) and time domain (root-mean square of successive differences [RMSSD], standard deviation of normal RR intervals [SDNN]), frequency domain (low [LF] and high frequency [HF]), and non-linear (standard deviation 1 [SD1] and SD2) HRV metrics. RHR showed excellent agreement whereas HF, LF, and SD2 showed poor agreement. For the remaining metrics, SDNN showed the strongest absolute and relative agreement, followed by SD1 and RMSSD. However, most HRV metrics exhibited heteroscedasticity or proportional bias, with greater error and underestimation at higher HRV values. M-index was unrelated to method difference scores, except for seated SD2 (

Indexed as

ElectrocardiographyHeart RateWearable Electronic DevicesAdultFemaleHumansMaleRestWristYoung Adultautonomic nervous systemcardiovasculardevice validationm-healthwearable technology

Identifiers

PMID40431957
PMCPMC12115943

What OpenQuestion holds

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LicenceCC BY
Read underepoch 390

Registered trials

None linked

Read under generation 80e0d062 · epoch 390. Bibliography from PubMed, PubMed Central and OpenAlex; grants from NIH RePORTER; trial links from ClinicalTrials.gov; estimates, votes and beliefs from the OpenQuestion graph.