submission - Independent Pilots Association

ex¡cnded or reduced. Although resulti shtrsed degrecs of impairmcn¡ from the acutc dterations in
slecp panern b¡ borh slcep groups. the l-t..-t hour sleepc¡s consistently showed grcater
imperrrrrnr CarskadonandDcnrcnr(lgtl.l9tllfound¡hate¡¡endrntthctotalt¡npinbedfrom
crght hours ro rcn in l8 ro 20yeu old sub.¡ccs allo*ed thcm to incre¡sc thci¡tual slccptiræon
more than onc hou¡. This resulrcd rn a significant irnProvcnrnt in da¡inr alcrùcs
"".og" whrch only appcared afær tlrc sccond nigbt of extended slccP. suggcsing a repayiog of slccp dcbt.
Thc rcsca¡chcrs fclt that ¡his improvcrrcnt supporrcd suggcstions thf cight horn of bcd tiræ roay
rcpnescnr a ch¡onic slccp dcprivarioo condition in young adults. Scorcs on ¡Icrocss sho*çd r
sair-step rcsponsc with tlrc lcogth of slccp per night as uæll ls witb tþ numbcr of nights. Thts
scones for ¡lcrtncss wc¡e bcttcr for æo bo¡rs of slccp tbaa for e[!Ç eight weæ bcAcr tb¡¡ ñvc,
r¡rd two nigbs with ñve bourl *cre baær thra scrca nights vith 6vt hou¡s wh¡cb scre bcacr
than scores witt no slccP.
In a stighrly difÏercnt rescarcb dcsigû.T/ehr (1993) for¡nd in e for¡¡-rek tcst thrt youog ¡ô¡lt¡
allowj to slccp as long .s tbcy dcsircd. slcpt in exoess of l0 bor¡r¡ e day ôuing tbc ñrst threc
days- This was followcd by thrcc days of abor¡t 9 bo{¡rs. Thc rernai¡dcr of tbc 2t days þveled ofr
ar an averagc of t.5 hours pcr night. Thcu habirual basc-linc slccp vrc7.2 bq¡rs. Tbc initially
higtrcr levcl of slecp is inærpreted as rcpayrænt of chrooic slccp dcbL A similar slæp
requirernent figure of t.4 hours was reporcd iDt¡¡.im
repon. Tbus both slecp eræosion srudics and
rcquirement aPPcars to bc be¡wcco t to 9 bor¡¡s
considcrabll hrgher than habirual slecP ñgures.
Thc bcncf ¡u of slecp are prerotl¡ considcrcd ro bc logarithmic in naru¡e. *ìth tbe initial boun
sho,* ing signifìcantJy trcåter bcr¡cfrts riu diminish as ooc approacbcs his or hcr opcimal shep
lcr.el This accounls for bow rna¡) can slccp less aod appç¿¡'to still fu¡ction nornrally Ho*erer
rhe t-r nd rn _:- i o I Roh¡e ( 1989) urd Taub, and Bc rgcr t 197ó) indicate t-hat during tåc frrst si¡ houn
of sleep. pr-,ormance is resrorcd tc a selrsi3s-tora lerel under normal conditions. although
ajenness and vigor ma¡ suU bt drm¡nrshe3 In llc hr-rurs bc¡'ond sü houn of slccpthc rcstoration
. pru-ess funher resrorcs alcrtncss aod vigor and the brarn's capaciry'to handle siruarions abovc
that of normal and for longer priods
An erample of rhis is besr iltr.rsr¡arcd b¡ Sarrrcl etd. (1997) wherc tlrc sccondof twonightflighs
sho,*cd a considcrablc rcducuon rn toleran.'c ilìd an increasc in fatrgrr aftcr only threc hou¡: of
flight *,hcreas on rhe ñnt nigbr fatigr.rc did oot sct r¡ unúl afrcr t bq¡rs. Tbr¡s. thc additioî¡¡
hou¡s scrved :Ls a rescrì'e capacity agains *orkload (Howin et al., l97t) or hours of dury (Sanæl
et al-. 1997. Gundcl et al-, 199?)
Lit¿rdture Ret ¡ex
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