A 1-μT extremely low-frequency electromagnetic field vs. sham control for mild-to-moderate hypertension: a double-blind, randomized study.

Hypertension research : official journal of the Japanese Society of Hypertension · 2011 · Benefit · Low evidence

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BenefitLow evidencePaper 4475

Compared with sham, the ELF-EMF group showed a significant difference in change in systolic blood pressure from baseline to end of the 4-week regimen (P=0.02), but not in diastolic blood pressure (P=0.21). Two participants in the ELF-EMF group reported mild h…

Study snapshot

PublicationHypertension research : official journal of the Japanese Society of Hypertension · 2011

Study typerandomized_trial

Reported directionBenefit

Evidence ratingLow

Abstract

The effects of extremely low-frequency electromagnetic fields (ELF-EMFs) on blood pressure (BP) are controversial. In this double-blind, randomized, sham-controlled study, we examined the effects of repeated exposure to a 1-μT ELF-EMF on BP in 20 humans with mild-to-moderate hypertension. Subjects were randomly assigned to either the ELF-EMF group or the sham group. Subjects in the ELF-EMF group were exposed to an ELF-EMF (6- and 8 Hz, respectively, peak magnetic field 1 μT, peak electric field 10 Vm(-1)) for at least two 10- to 15-min sessions per week, over a period of 4 weeks. In the sham group, the EMF-generating apparatus was not active. We obtained systolic and diastolic BP (SBP and DBP, respectively) measurements at registration and before and after each ELF-EMF exposure session. Subjects in the ELF-EMF and sham groups had mean ages of 52.8 and 55.1 years, and were exposed to a mean of 9.9 and 9.0 sessions, respectively. There was a significant difference between the ELF-EMF and sham groups with respect to change in SBP value between baseline and the end of the exposure regimen (P=0.02), but not with respect to change in DBP (P=0.21). There were no adverse events other than mild paresthesia of the hands of two subjects in the ELF-EMF group. Our results suggest that repeated exposure to an ELF-EMF has a BP-lowering effect on humans with mild-to-moderate hypertension.

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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

PopulationHumans with mild-to-moderate hypertension

Sample size20

ExposureELF · At least two 10–15 min sessions per week for 4 weeks (mean 9.9 sessions in ELF-EMF group; 9.0 in sham)

Evidence strengthLowConfidence: 78% · Peer reviewed: yes

Main findings

Outcomes measured

Systolic blood pressure (SBP)
Diastolic blood pressure (DBP)
Adverse events (paresthesia)

Limitations

Small sample size (n=20)
Short intervention/follow-up period (4 weeks)

View raw extracted JSON

{
  "study_type": "randomized_trial",
  "exposure": {
    "band": "ELF",
    "source": "other",
    "frequency_mhz": null,
    "sar_wkg": null,
    "duration": "At least two 10–15 min sessions per week for 4 weeks (mean 9.9 sessions in ELF-EMF group; 9.0 in sham)"
  },
  "population": "Humans with mild-to-moderate hypertension",
  "sample_size": 20,
  "outcomes": [
    "Systolic blood pressure (SBP)",
    "Diastolic blood pressure (DBP)",
    "Adverse events (paresthesia)"
  ],
  "main_findings": "Compared with sham, the ELF-EMF group showed a significant difference in change in systolic blood pressure from baseline to end of the 4-week regimen (P=0.02), but not in diastolic blood pressure (P=0.21). Two participants in the ELF-EMF group reported mild hand paresthesia; no other adverse events were reported.",
  "effect_direction": "benefit",
  "limitations": [
    "Small sample size (n=20)",
    "Short intervention/follow-up period (4 weeks)"
  ],
  "evidence_strength": "low",
  "confidence": 0.78,
  "peer_reviewed_likely": "yes",
  "keywords": [
    "extremely low-frequency electromagnetic fields",
    "ELF-EMF",
    "1 μT",
    "6 Hz",
    "8 Hz",
    "hypertension",
    "blood pressure",
    "double-blind",
    "randomized",
    "sham-controlled",
    "systolic blood pressure",
    "diastolic blood pressure",
    "paresthesia"
  ],
  "suggested_hubs": [
    {
      "slug": "who-icnirp",
      "weight": 0.2,
      "reason": "Study concerns health effects of ELF electromagnetic field exposure, relevant to general EMF health guidance discussions."
    }
  ]
}

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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: 10.1038/hr.2010.246
PubMed: 21248759

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