Does exposure to a radiofrequency electromagnetic field modify thermal preference in juvenile rats?

PloS one · 2014 · Mixed · Low evidence

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MixedLow evidencePaper 4684

Study snapshot

PublicationPloS one · 2014

Study typeanimal

Reported directionMixed

Evidence ratingLow

Abstract

Some studies have shown that people living near a mobile phone base station may report sleep disturbances and discomfort. Using a rat model, we have previously shown that chronic exposure to a low-intensity radiofrequency electromagnetic field (RF-EMF) was associated with paradoxical sleep (PS) fragmentation and greater vasomotor tone in the tail. Here, we sought to establish whether sleep disturbances might result from the disturbance of thermoregulatory processes by a RF-EMF. We recorded thermal preference and sleep stage distribution in 18 young male Wistar rats. Nine animals were exposed to a low-intensity RF-EMF (900 MHz, 1 V x m(-1)) for five weeks and nine served as non-exposed controls. Thermal preference was assessed in an experimental chamber comprising three interconnected compartments, in which the air temperatures (Ta) were set to 24°C, 28°C and 31°C. Sleep and tail skin temperature were also recorded. Our results indicated that relative to control group, exposure to RF-EMF at 31°C was associated with a significantly lower tail skin temperature (-1.6°C) which confirmed previous data. During the light period, the exposed group preferred to sleep at Ta = 31°C and the controls preferred Ta = 28°C. The mean sleep duration in exposed group was significantly greater (by 15.5%) than in control group (due in turn to a significantly greater amount of slow wave sleep (SWS, +14.6%). Similarly, frequency of SWS was greater in exposed group (by 4.9 episodes.h-1). The PS did not differ significantly between the two groups. During the dark period, there were no significant intergroup differences. We conclude that RF-EMF exposure induced a shift in thermal preference towards higher temperatures. The shift in preferred temperature might result from a cold thermal sensation. The change in sleep stage distribution may involve signals from thermoreceptors in the skin. Modulation of SWS may be a protective adaptation in response to RF-EMF exposure.

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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 typeanimal

Effect directionmixed

PopulationJuvenile/young male Wistar rats

Sample size18

ExposureRF · 900 MHz · 5 weeks

Evidence strengthLowConfidence: 78% · Peer reviewed: yes

Main findings

In 18 young male Wistar rats, 5-week exposure to low-intensity 900 MHz RF-EMF (1 V/m) was associated with a shift in thermal preference during the light period (exposed rats preferred 31°C vs controls 28°C). At 31°C, exposed rats had significantly lower tail skin temperature (-1.6°C) and had greater mean sleep duration (+15.5%) driven by increased slow wave sleep (+14.6%) and higher SWS episode frequency; paradoxical sleep did not differ significantly. No significant intergroup differences were observed during the dark period.

Outcomes measured

Thermal preference (preferred ambient temperature)
Sleep stage distribution (sleep duration, slow wave sleep, paradoxical sleep)
Tail skin temperature

Limitations

Small sample size (n=18; 9 exposed, 9 controls)
Animal model; generalizability to humans is uncertain
Exposure characterized by frequency and field strength (1 V/m) but SAR not reported in abstract
Some effects were period- and condition-specific (light period and/or 31°C; no differences during dark period)

View raw extracted JSON

{
  "study_type": "animal",
  "exposure": {
    "band": "RF",
    "source": null,
    "frequency_mhz": 900,
    "sar_wkg": null,
    "duration": "5 weeks"
  },
  "population": "Juvenile/young male Wistar rats",
  "sample_size": 18,
  "outcomes": [
    "Thermal preference (preferred ambient temperature)",
    "Sleep stage distribution (sleep duration, slow wave sleep, paradoxical sleep)",
    "Tail skin temperature"
  ],
  "main_findings": "In 18 young male Wistar rats, 5-week exposure to low-intensity 900 MHz RF-EMF (1 V/m) was associated with a shift in thermal preference during the light period (exposed rats preferred 31°C vs controls 28°C). At 31°C, exposed rats had significantly lower tail skin temperature (-1.6°C) and had greater mean sleep duration (+15.5%) driven by increased slow wave sleep (+14.6%) and higher SWS episode frequency; paradoxical sleep did not differ significantly. No significant intergroup differences were observed during the dark period.",
  "effect_direction": "mixed",
  "limitations": [
    "Small sample size (n=18; 9 exposed, 9 controls)",
    "Animal model; generalizability to humans is uncertain",
    "Exposure characterized by frequency and field strength (1 V/m) but SAR not reported in abstract",
    "Some effects were period- and condition-specific (light period and/or 31°C; no differences during dark period)"
  ],
  "evidence_strength": "low",
  "confidence": 0.78,
  "peer_reviewed_likely": "yes",
  "keywords": [
    "radiofrequency electromagnetic field",
    "RF-EMF",
    "900 MHz",
    "thermal preference",
    "thermoregulation",
    "sleep",
    "slow wave sleep",
    "paradoxical sleep",
    "tail skin temperature",
    "Wistar rats"
  ],
  "suggested_hubs": []
}

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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: 10.1371/journal.pone.0099007
PubMed: 24905635

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