A 20-min nap in athletes changes subsequent sleep architecture but does not alter physical performances after normal sleep or 5-h phase-advance conditions

Abstract

Purpose

The aim of the study was to examine the effects of a post-prandial 20 min nap on a short-term physical exercise and subsequent sleep in athletes keeping their usual sleep schedules and in 5-h phase-advance condition.

Methods

Sixteen healthy young male athletes (age 22.2 ± 1.7 years, non-habitual nappers) participated in the study. After a baseline 8-h time in bed in normal and 5-h advanced sleep schedules, a standardized morning and lunch in a laboratory environment, subjects underwent either a nap (20 min of sleep elapsed from 3 epochs of stage 1 or 1 epoch of stage 2), or a rest without sleep by lying in a bed, between 13:00 and 14:00 hours in non-shifted condition or 08:00 and 09:00 hours in shifted condition, after which anaerobic exercises were performed twice 2 h apart. Core body temperature was recorded throughout the study period.

Results

The nap extended sleep onset latency from 6.72 ± 3.83 to 11.84 ± 13.44 min, after shifted condition but did not modify sleep architecture of the post-trial night among athletes, whether shifted or not. Moreover, napping did not improve physical performance but it delayed acrophase and batyphase of core body temperature rhythm parameters.

Conclusion

Napping showed no reliable benefit on short-term performances of athletes exercising at local time or after a simulated jet lag.

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Abbreviations

AASM:

American Academy of Sleep Medicine

CBT:

Core body temperature

EEG:

Electroencephalogram

P mean :

Mean power

P peak :

Peak power

% N1:

Percentage in sleep stage 1

% N2:

Percentage in sleep stage 2

% N3:

Percentage in sleep stage 3

% REM:

Percentage in rapid eye movement

PSG:

Polysomnography

PTN1:

Post-tests night 1

PTN2:

Post-tests night 2

PTPAN1:

Post-tests night with phase advance 1

PTPAN2:

Post-tests night with phase advance 2

SE:

Sleep efficiency

SOL:

Sleep onset latency

TST:

Total sleep time

TTN1:

Total time in stage 1

TTN2:

Total time in stage 2

TTN3:

Total time in stage 3

TTREM:

Total time in stage REM

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Acknowledgments

The authors are grateful to the athletes who participated in this study. We also thank Gaëlle Brunotte for editorial assistance.

Conflict of interest

The authors declare that they have no conflict of interest.

Ethical standards

The experiments comply with the current laws of the country in which they were performed.

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Corresponding author

Correspondence to Elisabeth Petit.

Additional information

Communicated by Michael Lindinger.

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Petit, E., Mougin, F., Bourdin, H. et al. A 20-min nap in athletes changes subsequent sleep architecture but does not alter physical performances after normal sleep or 5-h phase-advance conditions. Eur J Appl Physiol 114, 305–315 (2014). https://doi.org/10.1007/s00421-013-2776-7

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Keywords

  • Simulated jet lag
  • Nap
  • Sleep
  • Exercise
  • Core body temperature