Sleep · lesson 7 of 11
Temperature & sleep hygiene
A cool, dark, quiet room and a bed your brain reads as 'sleep'.
5 min read · reviewed October 2026
Cool the room, cool the body
Falling asleep depends on your core temperature dropping. A bedroom that's too warm physically blocks that, which is why a cool room is one of the most reliable sleep upgrades. Aim for roughly 18°C / 65°F (most people do best somewhere in the 16–19°C / 60–67°F range).
A warm bath cools you down
A warm shower or bath 1–2 hours before bed feels paradoxical but works: it pulls blood to the skin and your core temperature drops afterward, helping trigger sleep.
The sleep-hygiene checklist
- Keep the bedroom cool — around 18°C / 65°F.
- Make it dark: blackout curtains or a sleep mask, cover stray LEDs.
- Make it quiet: earplugs or steady white/brown noise to mask disruptions.
- Reserve the bed for sleep (and sex) — no working or scrolling in it.
- If you can't sleep after ~20 minutes, get up, do something dull and dim, return when sleepy.
The bed is a cue, not a couch
When you only sleep in bed, your brain learns 'bed = sleep' and you drift off faster. Doing work, eating, or doomscrolling in bed trains the opposite association — this is the core idea behind stimulus-control therapy for insomnia.
Why does a warm bath an hour or two before bed help you fall asleep?
- It raises your core temperature to make you drowsy
- It causes your core temperature to drop afterward, which triggers sleep
- It only helps by being relaxing
- Warmth directly increases melatonin
Show the answer →
B.It causes your core temperature to drop afterward, which triggers sleep
The warmth sends blood to your skin; once you get out, your core temperature falls — and that drop is one of the body's signals to initiate sleep.