How nap length, timing, and sleep quality affect early morning performance

A 120-min nap sustained early morning performance better than a 60-min nap in a simulated nightshift schedule.

• Naps taken later in the night shift resulted in more efficient sleep.
• No significant negative effect on subsequent daytime and nocturnal sleep was observed following nocturnal naps.
• Timing of naps (earlier or later) did not influence performance on neurobehavioral tests.
• The role of slow wave sleep in supporting early morning performance remains unclear.
• Longer and later naps may be beneficial for work safety and sleep health during night shifts.

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