Physiol Behav. 2009 Mar 23;96(4-5):513-7. Epub 2008 Nov 27.
Self-reported 'sleep deficit' is unrelated to daytime sleepiness.
Anderson C, Platten CR, Horne JA.
Seemingly, many healthy adults have accrued a sleep debt, as determined by findings based on the multiple sleep latency test (MSLT). However, our recent, extensive survey found self-reported sleep deficit was not linked to daytime sleepiness determined by the Epworth sleepiness scale (ESS). Here, we report on the link between self-reported sleep deficit and gold standard measures of sleepiness: MSLT, Psychomotor vigilance test (PVT) and Karolinska Sleepiness Scale (KSS). Habitual sleep time in forty-three participants, from using a week long sleep diary and actiwatch data, compared with self-ratings of how much sleep they needed, provided estimates of apparent sleep deficit or otherwise. They were split into categories: 'sleep deficit' (Av. -47 min), 'sleep plus' (Av. 47 min) or 'neutral' (Av. 0+/-15 min), depicting perceived shortfall (or excess) sleep. Although the deficit group desired to sleep longer than the other groups, they actually obtained similar habitual nightly sleep as the neutral group, but less than the sleep plus group. 'Survival curves' based on those falling asleep during the MSLT showed no difference between the groups. Neither was there any difference between the groups for the PVT, KSS, or ESS. Here, factors other than sleepiness seem to influence self-perceived sleep deficits.