Caffeine and Sleep: The Timing Rule
You can fall asleep after a late coffee and still sleep worse — caffeine quietly steals deep sleep. Timing is everything.
The half-life problem
Caffeine has a half-life of ~5–6 hours — so half of a 3pm coffee is still in your system at 9pm. Even if you drop off, it lightens your sleep.
The rule
Have your last caffeine 8–10 hours before bed — for most people that means no coffee after early-to-mid afternoon. Sensitive? Cut it even earlier.
If you sleep badly and drink afternoon coffee, try a two-week cut-off experiment — many people are shocked at the difference.
Quick answers
Does caffeine affect sleep if I fall asleep fine?
Yes — it can reduce deep sleep even when you fall asleep normally, leaving you less rested.
When should I stop drinking coffee?
About 8–10 hours before bed. Earlier if you’re caffeine-sensitive.
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