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The effect of caffeine on subsequent sleep: A systematic review and meta-analysis

Sleep Medicine Reviews systematic review and meta-analysis (24 studies) reports that caffeine before bed shortens total sleep time, lowers sleep efficiency, prolongs sleep onset and wake after sleep onset, shifts sleep stages toward lighter N1 and away from deep N3/N4, and models timing thresholds (e.g. ~107 mg coffee ~8.8 h before bedtime).

Design

  • Type: systematic review + meta-analysis
  • Corpus: 24 studies on night-time sleep after caffeine
  • Goal: quantify sleep architecture shifts and pre-bed cut-off guidance

Headline pooled sleep changes (abstract)

  • Total sleep time: −45 min
  • Sleep efficiency: −7%
  • Sleep onset latency: +9 min
  • Wake after sleep onset: +12 min
  • Stage shifts: N1 duration +6.1 min and proportion +1.7%; deep sleep (N3/N4) duration −11.4 min and proportion −1.4%

Timing guidance (modelled in abstract)

  • Coffee ~107 mg / 250 mL: avoid closer than ~8.8 h before bedtime if the goal is to prevent TST loss
  • Pre-workout ~217.5 mg: abstract cites ~13.2 h window for the same TST protection target

Evidence hygiene

Laboratory polysomnography dominates included work—real-world mixed caffeine sources, genetics (CYP1A2), and habitual use still need individual calibration; pair with daytime performance trials under caffeine-ergogenic-supplementation without merging acute ergogenic claims with sleep debt behaviour.

Publication

Gardiner C, Weakley J, Burke LM, et al. Sleep Med Rev. 2023 Jun;69:101764. PMID 36870101.

Outcomes

  • Total Sleep Time
    -45
    min (Minutes)
  • Sleep Efficiency
    -7
    % (Percentage)
  • Sleep Onset Latency
    9
    min (Minutes)
  • Wake After Sleep Onset (WASO)
    12
    min (Minutes)
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