European Journal of Applied Physiology

, Volume 114, Issue 5, pp 1049–1056

Effects of dawn simulation on markers of sleep inertia and post-waking performance in humans

  • Andrew Thompson
  • Helen Jones
  • Warren Gregson
  • Greg Atkinson
Original Article

DOI: 10.1007/s00421-014-2831-z

Cite this article as:
Thompson, A., Jones, H., Gregson, W. et al. Eur J Appl Physiol (2014) 114: 1049. doi:10.1007/s00421-014-2831-z

Abstract

Purpose

To examine the effects of a simulated dawn during the last 30 min of sleep on the subsequent dissipation of sleep inertia and changes in simulated work and physical performance.

Methods

Eight participants, who reported difficulty with morning waking, were administered in a random order to a control (C) and a dawn simulation (DS) trial (starting 30 min prior to waking). Subjective ratings of sleep quality and alertness were obtained alongside measures of cognitive performance (addition and reaction time tasks measured at 5, 30 and 75 min after waking at habitual workday times). Physical performance was also measured 35 min after waking using a self-paced cycling protocol.

Results

After waking in DS, perceived sleep quality was 1.16 ± 0.89 (p = 0.01) points higher compared with C. Ratings of alertness were significantly higher in DS than C throughout the testing period (p = 0.04). Cognitive performance improved in both trials as time awake increased (p < 0.0005). On average, participants completed a greater number of additions in DS compared with C (69.5 ± 15.3 vs 66.9 ± 16.7, p = 0.03). Reaction times were also faster in DS compared with C (0.81 ± 0.07 s vs 0.86 ± 0.06 s, p < 0.0005). The self-paced time-trial was completed 21.4 s (4.7 %) quicker in DS (p = 0.07).

Conclusion

These data provide the first evidence that light exposure during the last 30 min of habitual sleep can increase subjective alertness and improve both cognitive and physical performance after waking.

Keywords

Artificial dawn Sleep inertia Performance Phototherapy 

Abbreviations

95 % CI

95 % Confidence interval

C

Control condition

DS

Dawn simulation condition

ELISA

Enzyme-linked immunosorbent assay

KSS

Karolinska sleepiness scale

RPE

Rating of perceived exertion

s

Second

SD

Standard deviation

Tc

Intestinal temperature

VAS

Visual analogue scale

Copyright information

© Springer-Verlag Berlin Heidelberg 2014

Authors and Affiliations

  • Andrew Thompson
    • 1
    • 2
  • Helen Jones
    • 2
  • Warren Gregson
    • 2
  • Greg Atkinson
    • 3
  1. 1.Clinical Epidemiology Group, Department of Epidemiology and Public HealthUniversity College LondonLondonUK
  2. 2.Research Institute for Sport and Exercise SciencesLiverpool John Moores UniversityLiverpoolUK
  3. 3.Health and Social Care InstituteTeesside UniversityMiddlesbroughUK

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