A cool bedroom, around 18 degrees
A cool room near 18 degrees deepens the slow-wave sleep that repairs you.
Recommended“Core temperature has to fall for sleep to begin. A cool room simply removes the obstacle.”
A consistent sleep and wake window
A fixed sleep window beats anything you could buy in a bottle.
Strong consensusAs the foundation ahead of any sleep supplement.
The strongest voice
“Regularity beats duration in most of the data we have. The body loves to know what time it is.”
In their own words
One faithful sentence per source, linked to the moment it was said; quiet chips mark where money is involved.
a sleep researcher recommend
“Sleep regularity predicts mortality outcomes more strongly than sleep duration in large cohort data.”
a sleep researcher · podcast episode · 00:23:41
a sleep medicine doctor recommend
“A fixed wake time is the single lever; the bedtime follows it within a week or two.”
a sleep medicine doctor · source video · 00:12:58
a psychiatrist recommend
“In mood disorders, stabilising the sleep window is often the first intervention that visibly helps.”
a psychiatrist · lecture · 00:36:24
a GP conditional
“Parents of young children need a gentler version of this advice, and that is fine.”
a GP · interview · 00:15:47
Worth discussing with your GP, especially if you take medication or are pregnant. Entrain describes what is publicly taught; it does not prescribe.
More from sleep
Nightly melatonin as a default
Our sources are genuinely split: an occasional tool, or a hormone best left alone.
Genuinely contested“Melatonin is a timing signal, not a sedative. Used as a nightly sledgehammer it often disappoints, and retail doses are far above what the pineal ever makes.”
Mouth taping at night
An early signal worth watching, once snoring and apnoea are ruled out.
An early signal“Nasal breathing at night is clearly worth encouraging. Whether tape is the right way to get there is a much smaller question than the internet suggests.”