Andrew Huberman· PhD
Historian Roger Ekirch documented pre-industrial “first/second sleep” — but the waking interval was roughly one hour, not two, and blocks were ~3–4 hours, not 4+4.
Loading…
The evidence is convergent. Multiple independent sources reach the same conclusion, the underlying mechanism is well-characterized, and even the field's most cautious voices treat it as worth doing.
Historian Roger Ekirch documented pre-industrial “first/second sleep” — but the waking interval was roughly one hour, not two, and blocks were ~3–4 hours, not 4+4.
Every Sunday: the week’s new conflicts and verdict changes — and nothing else.
Native comments, Twitter mentions, and Reddit threads about this claim — surfaced together so the conversation isn't fragmented across platforms.
Bookmarking — the dossier-vs-overview split is the right call. Most of the time I want overview; sometimes I want receipts.
Would love a "what would change this verdict" RSS feed. Sign me up if it exists.
there is good evidence that somewhere between about the 15th to 19th century seems to have ended during the kind of dezian era people were describing this behavior and they would wake up in the middle of the night after about 4 hours they would make food they would play music they would write they would make love it was a real thing
there is nothing in our biology that suggests that we should be sleeping in that way it seems to have been a social feature a social pressure
10 minutes of bright outdoor light within the first hour of waking anchors the circadian phase and improves sleep onset that night.
Morning sunlight exposure shifts the cortisol awakening response forward, improving daytime alertness.
Long-term morning sunlight reduces age-related macular degeneration risk.
Sleep regularity predicts all-cause mortality more strongly than sleep duration.
Tracking deep sleep on a wearable accurately reflects EEG-measured slow-wave sleep.
Caffeine has a half-life long enough that consumption after 2pm measurably degrades deep sleep in slow metabolizers.