Sleep inertia leaves people groggy after waking, and it is worse when waking from deep slow-wave sleep.

the verdict

SUPPORTED

the evidence backs this

Recorded sources

7 sources for · 1 against

Counts group repeated records of the same source within each side. They do not measure evidence strength or source independence.

Is it true that sleep inertia leaves people groggy after waking, and it is worse when waking from deep slow-wave sleep?

Yes. Multiple sources confirm that people feel groggy and impaired immediately after waking (sleep inertia), and a 2019 combined EEG-fMRI study found that awakening from N3 deep sleep produced the most robust changes, while a Cleveland Clinic reference states sleep inertia is most likely when waking from NREM stage 3 slow-wave sleep. One older study on slow-wave sleep deprivation complicates the deep-sleep half but addresses deprivation rather than awakening stage.

Verdict: SUPPORTED · 7 sources for, 1 against · Last checked 3 Oct 2026

The private library was unavailable for some searches in this check. Missing library results are not evidence against the claim.

Evidence for · 7

How To Get Rid of Sleep Inertia

Get citation

How To Get Rid of Sleep Inertia. (n.d.). health.clevelandclinic.org. https://health.clevelandclinic.org/sleep-inertia

Evidence against · 1

Slow‐wave sleep deprivation and waking function

1994

Get citation

WALSH, J. K., HARTMAN, P. G., & SCHWEITZER, P. K. (1994). Slow‐wave sleep deprivation and waking function. doi.org. https://doi.org/10.1111/j.1365-2869.1994.tb00099.x

See more details

More for · 6

Waking up is the hardest thing I do all day: Sleep inertia and sleep drunkenness -

Get citation

Waking up is the hardest thing I do all day: Sleep inertia and sleep drunkenness - PMC Lock. (n.d.). pmc.ncbi.nlm.nih.gov. https://doi.org/10.1016/j.smrv.2016.08.005

Module 7. Napping, an Important Fatigue Countermeasure, Sleep Inertia | NIOSH | CDCMinusSASstats

Get citation

Module 7. Napping, an Important Fatigue Countermeasure, Sleep Inertia | NIOSH | CDCMinusSASstats. (n.d.). cdc.gov. https://www.cdc.gov/niosh/work-hour-training-for-nurses/longhours/mod7/03.html

Hard to wake up? The cerebral correlates of sleep inertia assessed using combined behavioral, EEG and fMRI measures

2019

Get citation

Hard to wake up? The cerebral correlates of sleep inertia assessed using combined behavioral, EEG and fMRI measures. (2019). hal.science. https://doi.org/10.1016/j.neuroimage.2018.09.033

Impact of sleep inertia on visual selective attention for rare targets and the influence of chronotype

Get citation

Impact of sleep inertia on visual selective attention for rare targets and the influence of chronotype. (n.d.). cir.nii.ac.jp. https://doi.org/10.1111/jsr.12525

Loss of frontal regulator of vigilance during sleep inertia: A simultaneous EEG‐fMRI study

Get citation

Loss of frontal regulator of vigilance during sleep inertia: A simultaneous EEG‐fMRI study. (n.d.). cir.nii.ac.jp. https://doi.org/10.1002/hbm.25125

An Endogenous Circadian Rhythm in Sleep Inertia Results in Greatest Cognitive Impairment upon Awakening during the Biological Night

Get citation

An Endogenous Circadian Rhythm in Sleep Inertia Results in Greatest Cognitive Impairment upon Awakening during the Biological Night. (n.d.). cir.nii.ac.jp. https://doi.org/10.1177/0748730408318081

Receipt History

Anyone with this link can read the claim and its public receipt, including any personal information in that text. Open permanent receipt.

Check your own claim

Challenge the receipt

I have a source that contradicts this verdict I have a source that supports it No source: request a receipt review Requests are recorded for review. This does not start an automatic check or guarantee a response time.

Citation formatting by citeproc-js (Frank Bennett) and the Citation Style Language project. Source and licenses.

This receipt is an automated verdict against our published method · not an opinion about any author or publication.
Terms · Privacy · How verdicts work