submission - Independent Pilots Association

addit¡on murriplc missions and cumurarive days flling also in.'reased rhe pirors subjecurc need
for addirional resr bet$een missions. The tanir effect is the cumulatire effect of fatigue' As slecp
tirne increased Þfore a flighr the sub.¡cctire rest needed before the nert flight decreased'
SleeP P¡tterns During Tbe DeY
rypc of shift aod rotatioo. tbc¡e cao bc l¡
sboc/cd ürat slccp duration was dcPcDdcot oo thc ci¡cadian Pbasc'
ripino"tly reduced compared to nigbt tiræ sleep'
Thus da¡iræ slccp was
Tbc propcnsiry to slecp is high durin-g_the night and low during the day' But tbcrc is a gradient
effect in slecpincss. gir*".D six and r2 hor¡rs a*ake. sleepiness in conr¡ol subjecs increascd
scyeD pefccnt; bctwecn six a¡d lt hor¡rs, 28-37 Percent (Mi¡or & \\'aterhour' 1987: Minor et al'ì
l9g6). This is r-be rcsult of a myriad of otbcr rh¡lms-horrnond, sccrerory, rcmpe raure-rhat
orcbcg¡arc an rorernal envi¡onnpnt for action ã*i"g the day a¡d for r"st ar night. Tbe effect of
ci¡cadian rbyth' oo p"rro.."ncc is ilr¡strarcd i¡ tbc findings of a srccp deprivation srudy on
mulri-task pcrrorm-c e. Cæüer er et. (lgg4) poiDts out rha¡ alertness and prformancc would
normalry decli¡c as a function of ti¡nc since awake, exccpt s'hen co.rpred to the ci¡cadian risc in
body æmperaru.re, tle two functions stay rclatively søbiJe through most of thc waking boun Tbe
bcg.inning of a drop i¡ alert¡css stars th¡ec to fou¡ hours prior to normal bcdtinrc' At þdtirne
thcre is a suddcn å¿ ¿r.r-aic-lt-20 perccnt-fall irupcrformance a¡d dertness, coiociding
*ith tbe rapid drop in body tcmPerarurc'
Nighr s,ork uhrch rcquires daytinr srecp bas becn shor¡n ro reduce rhe amount of sleep obu:ned
w.herher on pcfroanent rugbt or roøting shifts (cotligan & Tepas, l9tó) [n quick changeovers
,^irh t bou¡s off ber*ecn sbfu. Tonerdetl (1990) found *orkers onl¡ acquircd 5-14 hours sleep
Kurumaram (1991)obscned that workers getting off at ló0o hfs and rcquued to began sgaln at
24OO boun srepr 2._15 hrs. or a similar shift cba-oge bur gening off ll00 hß and rerurning ro dun
u 2400 h¡s workers werc onry abre to get 3.0 hn sleep. The'. researcbers found a correraúon
(r=.95) bctwecn the hou¡s bcr*een shft a¡ld sleep duration' They concluded that at le¿st ló houn
off dury tirnc werc oeedcd bcrween shifu to insu¡e 7-8 hou¡ slecp, a conclusion reiterated in a
recent review (Kecklund & Akerscdt' 1995)'
T ra nsme ridia n OPerations
Tra¡rsræridian oçerations create simila¡ problems in attempting to \\ork uhen the bod¡ \\ants to
sleep and sleep nhen the body wants to be au'a\e The b'rggest chal)enge posed by multiple time-
Literature Rer iex
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