A pilot study investigating the impact of a caffeine-nap on alertness during a simulated night shift.
Level 2 - randomized trial
Crossover laboratory trial
PubMed 32819191 · doi:10.1080/07420528.2020.1804922
What was done
In a simulated shiftwork crossover laboratory pilot study, 6 participants (4 females, aged 21-36 years) consumed either 200 mg of caffeine or decaffeinated coffee (placebo) immediately prior to a 30-minute nap opportunity at 03:30 h. Vigilant attention and subjective fatigue were assessed across the 45 minutes post-nap.
What was found
The abstract reports no numerical values, effect sizes, or statistical significance levels. It states that relative to placebo, the caffeine-nap led to improved vigilant attention and subjective fatigue in the 45 minutes post-nap.
Why it matters
This pilot provides preliminary evidence that combining caffeine intake with a night nap may counteract post-nap sleep inertia during shiftwork.
Limits
The sample size is extremely small (n = 6), the environment was a simulated laboratory rather than an operational night shift, no quantitative outcomes or variance data were provided in the abstract, and monitoring ended at 45 minutes post-nap.
Cited by
- supports Taking a 25-minute nap immediately after drinking black coffee allows sleep to clear brain adenosine while caffeine binds to the receptor, providing boosted alertness for 4 hours.