Short daytime naps in a car seat to counteract daytime sleepiness: The effect of backrest angle

  1. Mitsuo HAYASHI1,*,
  2. Akiko ABE2

Article first published online: 21 FEB 2008

DOI: 10.1111/j.1479-8425.2008.00333.x

Issue

Sleep and Biological Rhythms

Sleep and Biological Rhythms

Volume 6, Issue 1, pages 34–41, January 2008

Additional Information

How to Cite

HAYASHI, M. and ABE, A. (2008), Short daytime naps in a car seat to counteract daytime sleepiness: The effect of backrest angle. Sleep and Biological Rhythms, 6: 34–41. doi: 10.1111/j.1479-8425.2008.00333.x

Author Information

  1. 1

    Graduate School of Integrated Arts and Sciences, Hiroshima University, Higashi-Hiroshima, and

  2. 2

    Human Science Research Department, Pigeon Corporation, Tsukuba, Japan

*Dr Mitsuo Hayashi, Graduate School of Integrated Arts and Sciences, Hiroshima University, 1-7-1, Kagamiyama, Higashi-Hiroshima 739-8521, Japan. Email: mhayasi@hiroshima-u.ac.jp

Publication History

  1. Issue published online: 21 FEB 2008
  2. Article first published online: 21 FEB 2008
  3. Received 22 May 2007/Accepted 29 October 2007.

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Keywords:

  • backrest angle;
  • short nap;
  • sleepiness;
  • vehicle accident

Abstract

A short nap of less than 30 min is an effective countermeasure to prevent afternoon sleepiness and resulting sleep-related accidents. This study was designed to confirm the effectiveness of napping on a car seat equivalent, and to compare two different backrest angles that are preferred by drivers. Eleven healthy university students (mean age 21.3 years, SD = 1.7) completed three experimental conditions: no-nap with the backrest positioned at 105°, and two 15-min naps, with the backrest inclined at 130° or 150°. Both naps with a 130° and 150° backrest incline reduced subjective sleepiness, improved task performance and suppressed slow eye movements (indicators of drowsiness) during the vigilance task. Napping with a backrest angle of 150° reduced subjective fatigue and improved reaction time further than that seen for naps at 130°. These results suggest that a short nap of 15 min in a car seat can counteract afternoon sleepiness and improve task performance. These effects are enhanced when the backrest angle is closer to the horizontal position.

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