Episode notes
Sleep calculators tell you to go to bed at exactly 10:46pm so you wake between cycles. That precision is invented.
Modern polysomnography puts the median sleep cycle at ninety-six minutes, not ninety, wrapped in enough individual variability that your own cycles may never land on the average. Here's where the number came from and what actually predicts how you'll feel in the morning.
SOURCES:
Ultradian sleep cycles, Sleep Health: Journal of the National Sleep Foundation, 2023 (6,064 cycles, 369 participants)
Dement & Kleitman, 1957
Written and fact-checked by Brent Burgess. Narration uses a synthetic voice model of his own voice.
This episode is general education and is not medical advice. Sleep problems can have serious underlying causes — talk to your doctor before changing medication, supplements, or treatment.