A 50-Hz electromagnetic field impairs sleep.

{
  "study_type": "other",
  "exposure": {
    "band": "ELF",
    "source": null,
    "frequency_mhz": 0.05,
    "sar_wkg": null,
    "duration": null
  },
  "population": "18 healthy subjects",
  "sample_size": 18,
  "outcomes": [
    "Total sleep time (TST)",
    "Sleep efficiency",
    "Stages 3+4 slow wave sleep (SWS)",
    "Slow wave activity (SWA)",
    "Circulating melatonin",
    "Growth hormone",
    "Prolactin",
    "Testosterone",
    "Cortisol"
  ],
  "main_findings": "In 18 healthy subjects, sleep during exposure to a 50 Hz/1 µT electrical field was associated with reduced total sleep time, sleep efficiency, stages 3+4 slow wave sleep, and slow wave activity compared with no exposure. Circulating melatonin, growth hormone, prolactin, testosterone, and cortisol were not affected.",
  "effect_direction": "mixed",
  "limitations": [
    "Small sample size (n=18)",
    "Exposure duration not reported in abstract",
    "Study design details (e.g., randomization/blinding/crossover) not reported in abstract"
  ],
  "evidence_strength": "low",
  "confidence": 0.74,
  "peer_reviewed_likely": "yes",
  "keywords": [
    "ELF EMF",
    "50 Hz",
    "1 µT",
    "sleep",
    "slow wave sleep",
    "slow wave activity",
    "melatonin",
    "hormones"
  ],
  "suggested_hubs": [
    {
      "slug": "occupational-exposure",
      "weight": 0.3,
      "reason": "Study concerns low-frequency (50 Hz) EMF exposure, which can be relevant to occupational/environmental ELF exposure contexts, though the source is not specified in the abstract."
    }
  ]
}