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

PAPER pubmed Bioelectromagnetics 2004 Randomized trial Effect: harm Evidence: Low

Read original paper → DOI: 10.1002/bem.10180 PMID: 15042625 Evidence Lab

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.

AI evidence extraction

At a glance

Study type

Randomized trial

Effect direction

harm

Population

Humans

Sample size

—

Exposure

ELF other · 0.037 MHz

Evidence strength

Low

Confidence: 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.

Suggested hubs

who-icnirp (0.32)
Human experimental study of ELF EMF with physiological endpoints relevant to exposure guidelines.

View raw extracted JSON

{
    "study_type": "randomized_trial",
    "exposure": {
        "band": "ELF",
        "source": "other",
        "frequency_mhz": 0.036999999999999998168132009368491708301007747650146484375,
        "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": 0.7399999999999999911182158029987476766109466552734375,
    "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": 0.320000000000000006661338147750939242541790008544921875,
            "reason": "Human experimental study of ELF EMF with physiological endpoints relevant to exposure guidelines."
        }
    ]
}

AI can be wrong. Always verify against the paper.

AI-extracted fields are generated from the abstract/metadata and may be incomplete or incorrect. This content is for informational purposes only and is not medical advice.

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