HoldsUp

FoundMyFitness · 2025-10-06 · Rhonda Patrick (host), Michael Grandner

Why You Can’t Sleep (and How to Fix It) | Dr. Michael Grandner

108 research-tied claims examined: 2 contradicted 5 overstated 9 context 78 supported 1 corroborated online 13 unverified

2

Contradicted by research

1:01:06Michael Grandnercontradictedhigh

Waking up with dream recall occurs because the person woke directly out of REM sleep.

"But so if you woke up and you remember a dream, it's cuz you woke up out of REM. That's all that's all that means." (said at 1:01:06)

The assertion that recalling a dream upon waking implies that the individual woke directly out of REM sleep is contradicted by sleep physiology research. While dream reports are generally more frequent, vivid, and narrative-like following awakenings from REM sleep, substantial scientific evidence demonstrates that dreaming and successful dream recall also regularly occur upon awakening from non-rapid eye movement (NREM) sleep stages (N1, N2, and N3). Laboratory polysomnography studies show that awakening from NREM sleep yields dream recall in 40% to 70% of awakenings, sharing specific posterior cortical activation patterns with REM dreaming.

2:15:48Michael Grandnercontradictedlow

A complete sleep cycle lasts approximately 90 to 100 minutes during nocturnal sleep, but can take 2 to 3 hours during daytime sleep.

"In the middle of the at night, during your regular sleep period, that'll take, you know, 90 to 100 minutes. During the day, it might take two to three hours to make it all the way through" (said at 2:15:48)

While standard nocturnal sleep cycles typically last around 90 to 110 minutes in adult humans, available physiological sleep research shows that daytime sleep cycles do not lengthen to 2 to 3 hours. Experimental studies comparing sleep architecture across night-time and daytime sleep periods (e.g., daytime sleep following sleep deprivation or postponed sleep) indicate that the duration of individual NREM-REM sleep cycles remains relatively stable or even shortens, despite increases in slow-wave sleep intensity. No evidence supports the claim that daytime sleep cycles double or triple in duration to 2 to 3 hours.

  • contradicts: The dynamics of the first sleep cycle. (Sleep 1991) · cited 36x in the literature
    "Eight subjects participated in an experiment in which sleep stages and electroencephalographic (EEG) power density during the first sleep cycles... were studied in a design involving 8, 4, 2 or 0 hr of progressively postponed night-time sleep. Each of these four manipulations was followed by a day-time sleep beginning at 1100 hr. No significant changes in the duration of the first sleep cycle appeared." (abstract, results)
    pubmed

Unverified means no publication matching the claim was located; it does not prove the claim false. Spotted an error? See the corrections policy - disputes from the people quoted are prioritized.