A pilot study investigating the impact of a caffeine-nap on alertness during a simulated night shift

ABSTRACT

Consuming coffee immediately prior to a nap, known as a caffeine-nap, has been shown to improve alertness during the day, but it is unknown whether a caffeine-nap is effective at reducing sleep inertia during the night. A simulated shiftwork cross-over laboratory study was conducted whereby participants (N = 6, 4 F, 21–36y) consumed 200 mg of caffeine, or decaffeinated coffee (placebo), immediately prior to a 30 min nap opportunity at 03:30 h. Compared to placebo, the caffeine-nap resulted in improved vigilant attention and subjective fatigue in the 45 min post-nap opportunity. The caffeine-nap may be useful in reducing sleep inertia in shift workers who nap on nightshift.

KEYWORDS:

• Coffee
• fatigue countermeasure
• napping
• shiftwork
• sleep inertia

Acknowledgements

The authors would like to thank the participants and research assistants who were involved in the study.

Disclosure of interest

The authors report no conflict of interest.

Additional information

Funding

This work was supported by a University of South Australia URIPA Mentoring & Seed Funding Grant.