Radio frequency electromagnetic field exposure in humans: Estimation of SAR distribution in the brain, effects on sleep and heart rate.

Bioelectromagnetics · 2003 · Mixed · Low evidence

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MixedLow evidencePaper 5281

Study snapshot

PublicationBioelectromagnetics · 2003

Study typerandomized_trial

Reported directionMixed

Evidence ratingLow

Abstract

In two previous studies we demonstrated that radiofrequency electromagnetic fields (RF EMF) similar to those emitted by digital radiotelephone handsets affect brain physiology of healthy young subjects exposed to RF EMF (900 MHz; spatial peak specific absorption rate [SAR] 1 W/kg) either during sleep or during the waking period preceding sleep. In the first experiment, subjects were exposed intermittently during an 8 h nighttime sleep episode and in the second experiment, unilaterally for 30 min prior to a 3 h daytime sleep episode. Here we report an extended analysis of the two studies as well as the detailed dosimetry of the brain areas, including the assessment of the exposure variability and uncertainties. The latter enabled a more in depth analysis and discussion of the findings. Compared to the control condition with sham exposure, spectral power of the non-rapid eye movement sleep electroencephalogram (EEG) was initially increased in the 9-14 Hz range in both experiments. No topographical differences with respect to the effect of RF EMF exposure were observed in the two experiments. Even unilateral exposure during waking induced a similar effect in both hemispheres. Exposure during sleep reduced waking after sleep onset and affected heart rate variability. Exposure prior to sleep reduced heart rate during waking and stage 1 sleep. The lack of asymmetries in the effects on sleep EEG, independent of bi- or unilateral exposure of the cortex, may indicate involvement of subcortical bilateral projections to the cortex in the generation of brain function changes, especially since the exposure of the thalamus was similar in both experiments (approx. 0.1 W/kg).

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Study typerandomized_trial

Effect directionmixed

PopulationHealthy young subjects

Sample sizeNot supplied

ExposureRF · 900 MHz · 1 W/kg · Intermittent exposure during an 8 h nighttime sleep episode; unilateral exposure for 30 min prior to a 3 h daytime sleep episode

Evidence strengthLowConfidence: 74% · Peer reviewed: yes

Main findings

Compared with sham exposure, NREM sleep EEG spectral power was initially increased in the 9–14 Hz range in both experiments, with no topographical differences and similar effects in both hemispheres even after unilateral exposure. Exposure during sleep reduced waking after sleep onset and affected heart rate variability; exposure prior to sleep reduced heart rate during waking and stage 1 sleep. Thalamus exposure was reported as approximately 0.1 W/kg in both experiments.

Outcomes measured

Brain dosimetry/SAR distribution in brain areas (including exposure variability and uncertainties)
Non-rapid eye movement (NREM) sleep EEG spectral power (9–14 Hz range)
Waking after sleep onset
Heart rate variability
Heart rate during waking and stage 1 sleep

Limitations

Sample size not reported in the provided abstract/metadata
Findings are reported as an extended analysis of two previous studies; details of randomization/blinding and statistical methods are not provided in the abstract
Exposure conditions differ between the two experiments (nighttime sleep vs pre-sleep waking exposure), limiting direct comparability

View raw extracted JSON

{
  "study_type": "randomized_trial",
  "exposure": {
    "band": "RF",
    "source": "mobile phone",
    "frequency_mhz": 900,
    "sar_wkg": 1,
    "duration": "Intermittent exposure during an 8 h nighttime sleep episode; unilateral exposure for 30 min prior to a 3 h daytime sleep episode"
  },
  "population": "Healthy young subjects",
  "sample_size": null,
  "outcomes": [
    "Brain dosimetry/SAR distribution in brain areas (including exposure variability and uncertainties)",
    "Non-rapid eye movement (NREM) sleep EEG spectral power (9–14 Hz range)",
    "Waking after sleep onset",
    "Heart rate variability",
    "Heart rate during waking and stage 1 sleep"
  ],
  "main_findings": "Compared with sham exposure, NREM sleep EEG spectral power was initially increased in the 9–14 Hz range in both experiments, with no topographical differences and similar effects in both hemispheres even after unilateral exposure. Exposure during sleep reduced waking after sleep onset and affected heart rate variability; exposure prior to sleep reduced heart rate during waking and stage 1 sleep. Thalamus exposure was reported as approximately 0.1 W/kg in both experiments.",
  "effect_direction": "mixed",
  "limitations": [
    "Sample size not reported in the provided abstract/metadata",
    "Findings are reported as an extended analysis of two previous studies; details of randomization/blinding and statistical methods are not provided in the abstract",
    "Exposure conditions differ between the two experiments (nighttime sleep vs pre-sleep waking exposure), limiting direct comparability"
  ],
  "evidence_strength": "low",
  "confidence": 0.74,
  "peer_reviewed_likely": "yes",
  "keywords": [
    "radiofrequency",
    "RF EMF",
    "900 MHz",
    "specific absorption rate",
    "SAR",
    "brain dosimetry",
    "sleep EEG",
    "NREM",
    "heart rate",
    "heart rate variability",
    "sham exposure",
    "unilateral exposure",
    "thalamus"
  ],
  "suggested_hubs": [
    {
      "slug": "who-icnirp",
      "weight": 0.22,
      "reason": "Human RF exposure study reporting SAR and physiological effects relevant to RF health risk assessment."
    }
  ]
}

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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.10103
PubMed: 12696086

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