TempoLife › Sleep questions › How late can I drink coffee before it affects my sleep?
How late can I drink coffee before it affects my sleep?
Caffeine has a half-life of about 5 hours, so a good rule is to stop sizeable amounts at least 8 hours before bed. An afternoon coffee still leaves a meaningful dose at bedtime.
Caffeine leaves the body slowly: its half-life is about 5 hours in a typical adult, meaning half is still in your system 5 hours after the cup, and a quarter after 10 hours. A 200 mg mug at 3pm still leaves roughly 65 mg at an 11pm bedtime — enough to measurably affect sleep in sensitive people.
A well-supported rule of thumb is to keep sizeable caffeine to at least 8 hours before bed. One much-cited study found that 400 mg taken even 6 hours before bedtime still cut measured sleep by more than an hour — often without the person feeling wide awake, because caffeine steals sleep quality as much as it delays sleep onset.
Individual clearance varies a lot (roughly 3 to 7 hours), and is slower in pregnancy and with some medications. If you sleep badly, making the afternoon coffee the small one — or the last one — is one of the cheapest fixes available.
Work it out for yourself
Answers are a start — tracking is the answer
TempoLife turns these numbers into your numbers: log food by photo, and see weight, sleep, steps and fasting in one place. Free to start.
More sleep questions
General information, not medical advice. Figures are mainstream reference values; individual needs vary.
