Sleep
Caffeineand Wake after sleep onset (WASO)
Only one source here so far, and it measured higher wake after sleep onset (WASO).
How sure anyone can be
Low certainty, level 2 of 4Further research is likely to change this.
The numbers reported
- 12 minutes
- minutes of wake after sleep onset
None of these sources gave a likely range — the band the real answer probably sits in — so how precise these numbers are is still an open question here.
One source, newest first
What we read is the published abstract, not the full paper, so a blank below may still be printed in the paper itself. A fixed rule worked this out from the source’s own fields. Nobody checked this rating by hand.
Systematic review, 2023
Low certainty, level 2 of 4The effect of caffeine on subsequent sleep: A systematic review and meta-analysis.
Sleep Med Rev. 2023;69:101764. doi:10.1016/j.smrv.2023.101764. PMID:36870101.
- Number reported
- 12 minutes
- Which way it went
- Higher
- Likely range
- Not in the abstract
- Source’s own words
- minutes of wake after sleep onset
- Who was studied
- Not stated in the abstract
- Compared with
- not stated in the abstract
- Amount taken
- Not in the abstract
- For how long
- Not in the abstract
- Disagreement between studies
- Not in the abstract
- Kind of record
- Journal article
How this rating was reachedstarts at High, 2 steps down: risk of bias and imprecision
- Starts at High
- Risk of bias brought it down to Moderatethe abstract reports no risk-of-bias or quality appraisal, so study limitations cannot be ruled outNot in the abstract
- Imprecision brought it down to Lowthe abstract reports no confidence interval for the estimateNot in the abstract
- Ends at Low2 steps down.
- Checked, nothing to step it down for
- indirectness
- Inconsistency
- No disagreement reported, and no count of studies behind it
Imprecision stops at the first check that applies; others may apply too.
Source saved; quote checked byte-for-byte against it by software; no signature.
What is still missing from these readings
- One gives no likely range, so how precise that number is is unknown.
- One do not say how many people took part.
- Amount taken — Not in the abstract.
- For how long — Not in the abstract.
Something nobody wrote down is never a zero and never a guess.
Still to read for Caffeine
Eight of the 19 things on our list for Caffeine have no reading here yet:
- Cognitive performance
- Estimated VO2max
- Fatigue
- Heart rate variability (RMSSD)
- Light sleep
- Number of awakenings
- Resting heart rate
- Serum cortisol (morning)
Still to read means nobody here has got to it, not that it was tried and did nothing or that no research exists. A pairing on no list is not a gap: we never set out to read it.
Read next
Caffeine
Ten other questions read for it
Sleep
29 questions read under it
Wake after sleep onset (WASO)
Two other ingredients read against it
Alphabetical, and by nothing else.
This is a library, not advice. No recommendation, no dose, no diagnosis, no ranking. We never ask about your symptoms, and nothing here is tailored to you.