The term Sleep Inertia was coined by Lubin et al. in 1976[1] and it refers to the post-sleep performance decrement that occurs immediately after awakening. Sleep inertia occurs after all sleep periods including night sleep, day sleep, and napping at any time. Performing safety critical activities with sleep inertia can be dangerous.
Quick Facts:
- Sleep inertia is a transient period immediately following awakening from sleep characterized by confusion, disorientation, low arousal, and deficits in various types of cognitive and motor performance[2]
- Sleep inertia effects can last for 3 to 4 hours after sleep, especially after intense sleep deprivation[3].
- Nocturnal confusion and decreased performance can occur after awakening from sleep and these vary with the depth of sleep, circadian phase and amount of prior sleep loss[4].
- When the awakenings from sleep are frequent, sleep inertia’s effects can be as severe as being unable to understand your own mother tongue language[5].
- Some tasks are more sensitive to sleep inertia’s effects than others. For example memory tasks, addition tasks and logical reasoning tasks are particularly affected by sleep inertia[6].
Resources:
- 3 Rules for Napping as a Fatigue Countermeasure
- Sleep Inertia: How long does it take you to wake up really?
- Waking up to the Call: Fighting grogginess after sleep
- Sleep Inertia Info-Graphic
- Waking up is the hardest thing I do all day: Sleep inertia and sleep drunkenness
Videos:
- W5, Canadian Pilots Sleeping While in Flight: An incident involving sleep inertia is discussed at 15:50 minutes into this video. The incident is discussed in detail in the Canadian TSB Aviation Investigation Report A11F0012
- Al Jazeera, Air India Jet Crashes in Mangalore: This incident is discussed in detail in the Government of India’s Ministry of Civil Aviation Report
References:
[1] Lubin, A., Hord, D., Tracy, M., & Johnson, L. (1976). Effects of exercise, bedrest and napping on performance decrements during 40 hours. Psychophysiology, 13, 334-339).
[2] Ferrara, M. & De Gennaro, L. (2000). The sleep inertia phenomenon during the sleep-wake transition: Theoretical operational issues. Aviation, Space and Environmental Medicine, 71, 843-848.
[3] See for examples:
(A) Naitoh, P. (1981). Circadian cycles and restorative power of naps. In L. Johnson, D. Tepas, W. Colquhoun, & M. Colligan, (Eds.), Biological rhythms, sleep and shift work (pp. 553-580). New York: Spectrum Publications.
(B) Haslam, D. (1985). Sleep deprivation and naps. Behavior Research Methods, Instruments, and Computers, 17, 46-54.
(C) Jewitt, M., Wyatt, J., Ritz-De Cecco, A., Khalsa S., Djik D., & Czeisler, C. (1999). Time course of sleep inertia dissipation in human performance and alertness. Journal of Sleep Research, 8, 1-8.
[4] See for examples:
(A) Dinges, D., Orne, M., & Orne, E. (1985). Assessing performance upon abrupt awakening from naps during quasi-continuous operations. Behavior Research Methods, Instruments, and Computers, 17, 37-45.
(B) Bonnet, M. (1985). Effect of sleep disruption on sleep, performance, and mood. Sleep, 8, 11-19).
[5] Bonnet, M. (1985). Effect of sleep disruption on sleep, performance, and mood. Sleep, 8, 11-19.
[6] See for examples:
(A) Stones, M. (1977). Memory performance after arousal from different sleep stages. British Journal of Psychology, 68, 177-181
(B) Naitoh, P. (1981). Circadian cycles and restorative power of naps. In L. Johnson, D. Tepas, W. Colquhoun, & M. Colligan, (Eds.), Biological rhythms, sleep and shift work (pp. 553-580). New York: Spectrum Publications.