Altered ultradian cortisol rhythmicity as a potential neurobiologic substrate for chronic insomnia.
Level 5 - mechanism / opinion, no new human data
Narrative review proposing a mechanistic framework without systematic review methodology or new human data
PubMed 29678398 · doi:10.1016/j.smrv.2018.03.003
What was done
The authors reviewed published literature on hypothalamic-pituitary-adrenal axis dysregulation and cortisol rhythmicity in chronic insomnia to evaluate how ultradian cortisol secretory patterns relate to sleep disruption.
What was found
The abstract reports no numerical findings or empirical data. It notes that cortisol pulses occur on an ultradian rhythm of every 60–120 minutes and proposes that aberrant nocturnal ultradian cortisol pulses, potentially functioning as a conditioned response, may trigger or prolong nocturnal awakenings and maintain wakefulness in chronic insomnia.
Why it matters
This review proposes shifting the neurobiological focus in chronic insomnia from broad 24-hour circadian cortisol curves to high-frequency ultradian pulsatility as a driver of nocturnal awakenings.
Limits
The abstract describes a narrative review and theoretical model without presenting original empirical data, quantitative results, or search methodology. It remains unclear whether nocturnal cortisol pulses cause awakenings or represent secondary responses to waking.
Cited by
- context Patients with sleep maintenance insomnia exhibit an abnormal spike in cortisol in the middle of the night that predicts awakenings.