Human head exposure to a 37 Hz electromagnetic field: effects on blood pressure, somatosensory perception, and related parameters.

Bioelectromagnetics · 2004 · Harm · Low evidence

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HarmLow evidencePaper 5232

Study snapshot

PublicationBioelectromagnetics · 2004

Study typerandomized_trial

Reported directionHarm

Evidence ratingLow

Abstract

Previous studies have shown that exposure to an electromagnetic field (EMF) of 37 Hz at a flux density of 80 microT peak enhances nociceptive sensitivity in mice. Here we examined the effects on pain sensitivity and some indexes of cardiovascular regulation mechanisms in humans by measuring electrical cutaneous thresholds, arterial blood pressure, heart rate and its variability, and stress hormones. Pain and tolerance thresholds remained unchanged after sham exposure but significantly decreased after electromagnetic exposure. Systolic blood pressure was significantly higher during electromagnetic exposure and heart rate significantly decreased, both during sham and electromagnetic exposure, while the high frequency (150-400 mHz) component of heart rate variability, which is an index of parasympathetic activity, increased as expected during sham exposure but remained unchanged during electromagnetic exposure. Cortisol significantly decreased during sham exposure only. These results show that exposure to an EMF of 37 Hz also alters pain sensitivity in humans and suggest that these effects may be associated with abnormalities in cardiovascular regulation.

Machine Enhanced Logic

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 directionharm

PopulationHumans

Sample sizeNot supplied

ExposureELF · 0.037 MHz

Evidence strengthLowConfidence: 74% · Peer reviewed: yes

Main findings

After sham exposure, pain and tolerance thresholds were unchanged, but they significantly decreased after 37 Hz EMF exposure (80 microT peak). Systolic blood pressure was significantly higher during EMF exposure; heart rate significantly decreased during both sham and EMF exposure. The high-frequency component of heart rate variability increased during sham exposure but remained unchanged during EMF exposure, and cortisol significantly decreased during sham exposure only.

Outcomes measured

pain sensitivity (pain and tolerance thresholds; electrical cutaneous thresholds)
arterial blood pressure (systolic)
heart rate
heart rate variability (high frequency 150–400 mHz component; parasympathetic activity index)
stress hormones (cortisol)

Limitations

Sample size not reported in the provided abstract/metadata.
Exposure duration and detailed protocol (e.g., randomization/blinding) not described in the provided abstract/metadata.
Only short-term/acute effects are described; longer-term outcomes not addressed in the provided abstract/metadata.

View raw extracted JSON

{
  "study_type": "randomized_trial",
  "exposure": {
    "band": "ELF",
    "source": "other",
    "frequency_mhz": 0.037,
    "sar_wkg": null,
    "duration": null
  },
  "population": "Humans",
  "sample_size": null,
  "outcomes": [
    "pain sensitivity (pain and tolerance thresholds; electrical cutaneous thresholds)",
    "arterial blood pressure (systolic)",
    "heart rate",
    "heart rate variability (high frequency 150–400 mHz component; parasympathetic activity index)",
    "stress hormones (cortisol)"
  ],
  "main_findings": "After sham exposure, pain and tolerance thresholds were unchanged, but they significantly decreased after 37 Hz EMF exposure (80 microT peak). Systolic blood pressure was significantly higher during EMF exposure; heart rate significantly decreased during both sham and EMF exposure. The high-frequency component of heart rate variability increased during sham exposure but remained unchanged during EMF exposure, and cortisol significantly decreased during sham exposure only.",
  "effect_direction": "harm",
  "limitations": [
    "Sample size not reported in the provided abstract/metadata.",
    "Exposure duration and detailed protocol (e.g., randomization/blinding) not described in the provided abstract/metadata.",
    "Only short-term/acute effects are described; longer-term outcomes not addressed in the provided abstract/metadata."
  ],
  "evidence_strength": "low",
  "confidence": 0.74,
  "peer_reviewed_likely": "yes",
  "keywords": [
    "37 Hz",
    "ELF EMF",
    "80 microT",
    "human head exposure",
    "pain threshold",
    "tolerance threshold",
    "blood pressure",
    "heart rate",
    "heart rate variability",
    "parasympathetic activity",
    "cortisol"
  ],
  "suggested_hubs": [
    {
      "slug": "who-icnirp",
      "weight": 0.32,
      "reason": "Human experimental study of ELF EMF with physiological endpoints relevant to exposure guidelines."
    }
  ]
}

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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.10180
PubMed: 15042625

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