Effects of Context on Sleepiness Self‐Ratings during Repeated Partial Sleep Deprivation

Ratings of subjective sleepiness are often used in laboratory and field studies of sleep loss and shifted sleep hours. Some studies suggest that such ratings might fail to reflect sleepiness as shown in physiology or performance. One reason for this may be the influence of the context of the rating. Social interaction or physical activity may mask latent sleepiness. The present study attempted to approach this question. Nine subjects participated in a partial sleep‐deprivation experiment (five days of 4 h of time in bed [TIB]), preceded by two baseline days (8 h TIB) and followed by three recovery days (8 h TIB). Sleepiness was self‐rated on the Karolinska Sleepiness Scale (KSS; scores of 1–9) after a period of relaxation, after a reaction‐time test, and after 30 min of free activities. The results showed a strong increase in subjective sleepiness during sleep restriction and a significant difference between conditions. Free activity reduced the self‐rated subjective sleepiness by 1.1 KSS units compared to the level of sleepiness self‐rated at the end of the reaction‐time test. Thus, the results of this study indicate that the context of a sleepiness rating affects the outcome of the rating.

[1]  T. Åkerstedt,et al.  Sleepiness and Performance in Response to Repeated Sleep Restriction and Subsequent Recovery during Semi‐Laboratory Conditions , 2008, Chronobiology international.

[2]  Torbjörn Åkerstedt,et al.  The effects of asking for verbal ratings of sleepiness on sleepiness and its masking effects on performance , 2007, Clinical Neurophysiology.

[3]  M. Smolensky,et al.  Ethics, Standards, and Procedures of Animal and Human Chronobiology Research , 2006, Chronobiology international.

[4]  T. Åkerstedt,et al.  Comment on Short-Term Variation in Subjective Sleepiness , 2005, Perceptual and motor skills.

[5]  A. Spielman,et al.  A standard procedure enhances the correlation between subjective and objective measures of sleepiness. , 2004, Sleep.

[6]  D. Dinges,et al.  The cumulative cost of additional wakefulness: dose-response effects on neurobehavioral functions and sleep physiology from chronic sleep restriction and total sleep deprivation. , 2003, Sleep.

[7]  Maria L. Thomas,et al.  Patterns of performance degradation and restoration during sleep restriction and subsequent recovery: a sleep dose‐response study , 2003, Journal of sleep research.

[8]  Y. Hishikawa,et al.  Physical activity increases the dissociation between subjective sleepiness and objective performance levels during extended wakefulness in human , 2002, Neuroscience Letters.

[9]  D. Dijk,et al.  EEG and ocular correlates of circadian melatonin phase and human performance decrements during sleep loss. , 1999, American journal of physiology. Regulatory, integrative and comparative physiology.

[10]  F. Lucidi,et al.  Effects of different sleep reductions on daytime sleepiness. , 1999, Sleep.

[11]  R. Kronauer,et al.  Dose-response relationship between sleep duration and human psychomotor vigilance and subjective alertness. , 1999, Sleep.

[12]  J. Horne,et al.  Suppression of sleepiness in drivers: combination of caffeine with a short nap. , 1997, Psychophysiology.

[13]  G. Kecklund,et al.  Relations between performance and subjective ratings of sleepiness during a night awake. , 1994, Sleep.

[14]  T. Åkerstedt,et al.  Subjective and objective sleepiness in the active individual. , 1990, The International journal of neuroscience.

[15]  T. Åkerstedt,et al.  Sleepiness on the job: continuously measured EEG changes in train drivers. , 1987, Electroencephalography and clinical neurophysiology.

[16]  M. Carskadon,et al.  Effects of Total Sleep Loss on Sleep Tendency , 1979, Perceptual and motor skills.

[17]  A. Kjellberg,et al.  Effects of 24-hour sleep deprivation on rate of decrement in a 10-minute auditory reaction time task. , 1972, Journal of experimental psychology.

[18]  Hans P. A. Van Dongen,et al.  Sleep debt and cumulative excess wakefulness , 2003 .

[19]  G. Kecklund,et al.  Change from an 8-hour shift to a 12-hour shift, attitudes, sleep, sleepiness and performance. , 1998, Scandinavian journal of work, environment & health.

[20]  L C Johnson,et al.  Subjective and objective measures of sleepiness: effect of benzodiazepine and caffeine on their relationship. , 1991, Psychophysiology.

[21]  C. Karlsson,et al.  CIRCADIAN VARIATIONS IN PERFORMANCE, PSYCHOLOGICAL RATINGS, CATECHOLAMINE EXCRETION AND URINE FLOW DURING PROLONGED SLEEP DEPRIVATION , 1970 .

[22]  H. J. Eysenck,et al.  Researches on the measurement of human performance. , 1951 .