Editing Sleep debt (section)

==Scientific debate==

There is debate among researchers as to whether the concept of sleep debt describes a measurable phenomenon. The September 2004 issue of the journal ''Sleep'' contains dueling editorials from two leading sleep researchers, [[David F. Dinges]]<ref>{{cite journal | vauthors = Dinges DF | title = Sleep debt and scientific evidence | journal = Sleep | volume = 27 | issue = 6 | pages = 1050–2 | date = September 2004 | pmid = 15532196 | authorlink1 = David F. Dinges }}</ref> and [[Jim Horne (neuroscientist)|Jim Horne]].<ref>{{cite journal | vauthors = Horne J | title = Is there a sleep debt? | journal = Sleep | volume = 27 | issue = 6 | pages = 1047–9 | date = September 2004 | pmid = 15532195 }}</ref> A 1997 experiment conducted by psychiatrists at the [[Perelman School of Medicine at the University of Pennsylvania|University of Pennsylvania School of Medicine]] suggested that cumulative nocturnal sleep debt affects daytime sleepiness, particularly on the first, second, sixth, and seventh days of sleep restriction.<ref>{{cite journal | vauthors = Dinges DF, Pack F, Williams K, Gillen KA, Powell JW, Ott GE, Aptowicz C, Pack AI | title = Cumulative sleepiness, mood disturbance, and psychomotor vigilance performance decrements during a week of sleep restricted to 4-5 hours per night | journal = Sleep | volume = 20 | issue = 4 | pages = 267–77 | date = April 1997 | pmid = 9231952 }}</ref>

In one study, subjects were tested using the [[psychomotor vigilance task]] (PVT). Different groups of people were tested with different sleep times for two weeks: 8 hours, 6 hours, 4 hours, and total [[sleep deprivation]]. Each day, they were tested for the number of lapses on the PVT. The results showed that, as time went by, each group's performance worsened, with no sign of any stopping point. Moderate sleep deprivation was found to be detrimental; people who slept 6 hours a night for 10 days had similar results to those who were completely sleep deprived for 1 day.<ref>Walker, M.P. (2009, October 21). *Sleep Deprivation III: Brain consequences – Attention, concentration and real life.* Lecture given in Psychology 133 at the University of California, Berkeley, CA.</ref><ref>{{cite journal | vauthors = Knutson KL, Spiegel K, Penev P, Van Cauter E | title = The metabolic consequences of sleep deprivation | journal = Sleep Medicine Reviews | volume = 11 | issue = 3 | pages = 163–78 | date = June 2007 | pmid = 17442599 | pmc = 1991337 | doi = 10.1016/j.smrv.2007.01.002 | authorlink1 = Kristen L Knutson }}</ref>