Does exposure to an artificial ULF magnetic field affect blood pressure, heart rate variability and mood?

Biomedicine & pharmacotherapy = Biomedecine & pharmacotherapie · 2004 · No effect · Very low evidence

← Research stream

No effectVery low evidencePaper 3675

Study snapshot

PublicationBiomedicine & pharmacotherapy = Biomedecine & pharmacotherapie · 2004

Study typeother

Reported directionNo effect

Evidence ratingVery low

Abstract

The aim of this study was to determine whether an artificial magnetic field with an amplitude and frequency equivalent to those of geomagnetic pulsations during geomagnetic storms could affect physiology and psychology. Three healthy volunteers wore anambulatory BP monitor and an ECG recorder around the clock for 12 consecutive weekends in Winnipeg, Manitoba, Canada. In a room shielded against ELF and VLF waves, they were exposed for 8 hours per week to either a 50 nT 0.0016 Hz or a sham magnetic field at one of six circadian stages. Real exposure randomly alternated with sham exposure. They provided saliva and recorded mood and reaction time every 4 hours while awake. Systolic (S) and diastolic (D) blood pressure (BP), and heart rate (HR) were recorded every 30 minutes. Spectral analysis of HR variability (HRV) was performed using the maximum entropy method and a complex demodulation method. For these variables, daily means were compared between real and sham exposure, using paired t-tests. Their circadian MESOR, amplitude, and acrophase were analyzed and summarized using single cosinor and population-mean cosinor. Circadian rhythms were demonstrated for HR, SBP, DBP for sham exposure, salivary flow rate, positive affect, vigor, and subjective alertness (p < 0.001, -0.02). One participant showed higher HR, lower LF, HF, and VLF powers, and a steeper power-law slope (p < 0.005, -0.0001) in an early night exposure to the real magnetic field, but not in other circadian stages. There was no significant difference between circadian responses to real and sham exposure in any variable at any circadian stage.

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 typeother

Effect directionno_effect

PopulationThree healthy volunteers in Winnipeg, Manitoba, Canada

Sample size3

ExposureULF · 1.6e-06 MHz · 8 hours per week for 12 consecutive weekends

Evidence strengthVery lowConfidence: 74% · Peer reviewed: yes

Main findings

In a shielded room, three volunteers were exposed to a 50 nT, 0.0016 Hz magnetic field or sham for 8 hours/week at one of six circadian stages, with real and sham alternating. One participant showed changes in HR and HRV measures during an early-night real-field exposure, but not at other circadian stages. Overall, no significant differences were found between circadian responses to real versus sham exposure for any variable at any circadian stage.

Outcomes measured

blood pressure (systolic, diastolic)
heart rate
heart rate variability (spectral powers: LF, HF, VLF; power-law slope)
salivary flow rate
mood (positive affect, vigor, subjective alertness)
reaction time

Limitations

Very small sample size (n=3)
Findings of altered HR/HRV were observed in only one participant and only at one circadian stage

View raw extracted JSON

{
  "study_type": "other",
  "exposure": {
    "band": "ULF",
    "source": "other",
    "frequency_mhz": 1.6e-06,
    "sar_wkg": null,
    "duration": "8 hours per week for 12 consecutive weekends"
  },
  "population": "Three healthy volunteers in Winnipeg, Manitoba, Canada",
  "sample_size": 3,
  "outcomes": [
    "blood pressure (systolic, diastolic)",
    "heart rate",
    "heart rate variability (spectral powers: LF, HF, VLF; power-law slope)",
    "salivary flow rate",
    "mood (positive affect, vigor, subjective alertness)",
    "reaction time"
  ],
  "main_findings": "In a shielded room, three volunteers were exposed to a 50 nT, 0.0016 Hz magnetic field or sham for 8 hours/week at one of six circadian stages, with real and sham alternating. One participant showed changes in HR and HRV measures during an early-night real-field exposure, but not at other circadian stages. Overall, no significant differences were found between circadian responses to real versus sham exposure for any variable at any circadian stage.",
  "effect_direction": "no_effect",
  "limitations": [
    "Very small sample size (n=3)",
    "Findings of altered HR/HRV were observed in only one participant and only at one circadian stage"
  ],
  "evidence_strength": "very_low",
  "confidence": 0.74,
  "peer_reviewed_likely": "yes",
  "keywords": [
    "ULF magnetic field",
    "geomagnetic pulsations",
    "geomagnetic storms",
    "blood pressure",
    "heart rate variability",
    "mood",
    "circadian stage",
    "sham exposure",
    "50 nT",
    "0.0016 Hz"
  ],
  "suggested_hubs": []
}

AI can be wrong. Always verify against the paper.

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: 10.1016/s0753-3322(04)80004-0
PubMed: 15754834

Read the original paper →

Related papers

← Back to the Research Library