The Short-Term Effect of Occupational Levels of 50 Hz Electromagnetic Field on Human Heart Rate Variability.

Bioelectromagnetics · 2021 · Benefit · Moderate evidence

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BenefitModerate evidencePaper 5616

Within-subject analysis showed significant HR deceleration in both EMF and sham groups. HRV indices (SDNN, RMSSD, LF, HF) increased only in the EMF group and remained stable in the sham group; between-group comparisons found higher SDNN, RMSSD, LF, and HF in …

Study snapshot

PublicationBioelectromagnetics · 2021
Study typerandomized_trial
Reported directionBenefit
Evidence ratingModerate

Abstract

Previous studies have indicated that there is no consensus on the effects of extremely low-frequency electromagnetic (ELF-EMF) exposure on the cardiovascular system. This study aimed to explore the short-term effect of ELF-EMF exposure on heart rate (HR) and HR variability (HRV). The sample consisted of 34 healthy males aged 18-27 years. The participants were randomly assigned to the EMF (n = 17) or the Sham group (n = 17). We employed a double-blind repeated-measures design consisting of three 5 min experimental periods. The chest region of each individual in the EMF group was exposed to 50 Hz, 28 μT, linear polarized, continuous EMF during the EMF exposure period. HR and HRV data were recorded continuously by using a photoplethysmography sensor. Within-subject statistical analysis indicated a significant HR deceleration in both the EMF and Sham groups. However, the standard deviation of the NN intervals (SDNN), root mean square of successive differences (RMSSD), low-frequency (LF), and high-frequency (HF) powers increased only in the EMF group and remained stable in the Sham group. We also compared the same HRV indices measured during the EMF and Sham periods between the two experimental groups. The between-subject analysis results demonstrated significantly higher SDNN, RMSSD, LF, and HF values in the EMF group than in the Sham group. The LF/HF ratio did not change significantly within and between groups. On the basis of these results, we concluded that short-term exposure of the chest region to ELF-EMF could potentially enhance parasympathetic predominance during the resting condition. Bioelectromagnetics. 2021;42:60-75. © 2020 Bioelectromagnetics Society.

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AI evidence extraction

Structured fields below were generated from the paper’s abstract and metadata to make the evidence easier to inspect. Automated extraction may be incomplete or incorrect; verify important details against the original paper.

Study typerandomized_trial
Effect directionbenefit
Population34 healthy males aged 18–27 years
Sample size34
ExposureELF · Three 5 min experimental periods; EMF exposure during one 5 min period
Evidence strengthModerateConfidence: 78% · Peer reviewed: yes

Main findings

Within-subject analysis showed significant HR deceleration in both EMF and sham groups. HRV indices (SDNN, RMSSD, LF, HF) increased only in the EMF group and remained stable in the sham group; between-group comparisons found higher SDNN, RMSSD, LF, and HF in the EMF group than in the sham group, while LF/HF did not change significantly.

Outcomes measured

  • Heart rate (HR)
  • Heart rate variability (HRV)
  • SDNN
  • RMSSD
  • Low-frequency (LF) power
  • High-frequency (HF) power
  • LF/HF ratio

Limitations

  • Small sample size (n=34)
  • Participants were healthy young males only (18–27 years)
  • Short-term exposure only (5 min exposure period)
  • Exposure localized to chest region; may not generalize to other exposure scenarios
View raw extracted JSON
{
  "study_type": "randomized_trial",
  "exposure": {
    "band": "ELF",
    "source": "occupational",
    "frequency_mhz": null,
    "sar_wkg": null,
    "duration": "Three 5 min experimental periods; EMF exposure during one 5 min period"
  },
  "population": "34 healthy males aged 18–27 years",
  "sample_size": 34,
  "outcomes": [
    "Heart rate (HR)",
    "Heart rate variability (HRV)",
    "SDNN",
    "RMSSD",
    "Low-frequency (LF) power",
    "High-frequency (HF) power",
    "LF/HF ratio"
  ],
  "main_findings": "Within-subject analysis showed significant HR deceleration in both EMF and sham groups. HRV indices (SDNN, RMSSD, LF, HF) increased only in the EMF group and remained stable in the sham group; between-group comparisons found higher SDNN, RMSSD, LF, and HF in the EMF group than in the sham group, while LF/HF did not change significantly.",
  "effect_direction": "benefit",
  "limitations": [
    "Small sample size (n=34)",
    "Participants were healthy young males only (18–27 years)",
    "Short-term exposure only (5 min exposure period)",
    "Exposure localized to chest region; may not generalize to other exposure scenarios"
  ],
  "evidence_strength": "moderate",
  "confidence": 0.78,
  "peer_reviewed_likely": "yes",
  "keywords": [
    "extremely low-frequency EMF",
    "ELF-EMF",
    "50 Hz",
    "28 μT",
    "occupational exposure",
    "double-blind",
    "sham-controlled",
    "heart rate variability",
    "parasympathetic",
    "SDNN",
    "RMSSD",
    "LF",
    "HF"
  ],
  "suggested_hubs": [
    {
      "slug": "occupational-exposure",
      "weight": 0.9,
      "reason": "Study describes exposure at occupational levels and uses an experimental design relevant to workplace ELF-EMF."
    }
  ]
}
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AI-extracted fields are generated from the abstract and metadata and may be incomplete or incorrect. This material is for informational purposes and is not medical advice.

Identifiers and source

DOI: 10.1002/bem.22308
PubMed: 33211349

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