submission - Independent Pilots Association

.igilance performance \r'ere found the follo*ing de-"" *hen sleep'*as reduced belo* th¡ee houn
foi one night or [e*er than fir'e hours for tuo conrccutive nights. Cankadon. Haney and Dcment
( lggl ) found ¡ncreased daltime sleepiness. as rrriured by the ¡vlSLT. after one night of slerp
reduced ro four hours in a group of l2-year-olds. although pcrformancc decrements \¡'ere Dot
found.
Restriction of sleep in young adults to jusr 5 houn increases sleepiness on the MSLT the next dar
by 25 pcrcenr and by 60 pcrccnt the scvcnth day rCankadon & Derncnt, l98l). rWhco slecp was
rcduccd to five hours or less. perfoffnancc and dcrtncss sr¡ffered and slecpincss significantly
increascd (Wilkinson et al., 196ó; Johnsoo, l9t2: Carskadon & Roth, l99l:Gillbcrg & Akerstcdt
1994; Taub lt, Bergcr, 1973; Ca¡skadon ll Denrnr. lgtl). A reccnt snrdy of Ausralian tn¡ckcrs
for¡nd that 20 perccnt of drivcrs slecp 6 hours or less a¡d æcor¡nt for 40 pcrcent of thc hazardou
cyenrs rcportcd (Arnold et al., 1997\. Drring Opcration Descn Storm, tbc pilots of thc Military
Airlifr Cómmand flighs obtaining only I I hor¡¡s slecp in 48 hours werc found to bc in dangcr of
experiencing diffrculties i¡ concentrating and su¡ ing awake (Ncvillc et al., 1992). Furthcr pilot
oblrvarions indicated that to prevent fuigue in tbesc pilos. at least l7 hours of slccp in 4t bours
(?.5 hou¡J 24 hours) werc requi¡ed
Dinges (1997)showed sigoificant cumulative effects of slecp debt on waking functions wbcn
subþs werc rcsrricæd from thci¡ usual 7.41 hor.rn slecp to only 4.9t hou¡s (sd .57 hrs) of usual
steep (67 percenr). Across rhe scven oreigbtda¡sof slecp rcstrioion subjccs showcd increasing
levels of subjecrive sleepiness, fatigue, confusion. tension, nrcntal exhaustion indicators, sùess,
and lapses in,-reasing ih frequency and duration These escalating cbanges prol'ide strong
evidence that partial sleep rcstriction similar ro ¡-hat experienced by pi.los has cumularive effecs
simlla¡ to thosc found rn total or morc excrÊfne pafttal rcstriccion.
In conrra-st. Hocker's r1986)anal¡sis of pa,rid sleep depriration srudy findings revealed rrunimal
performan.-e changes bur rhere *ere sigruiì:¡nt rtJuctions in rieila¡ce, efhciency. and increased
subjective sleepiness *ith a¡d mood detenoratloo
These resulrs suggesr that rcducing rest b¡ an hour should have linle impact on a pilot's
pe rformance ri rhe pilor is *ell rested prior to the reduced rest. If the pilot is suffenng from sleep
debt prior to the reduced rest. there may be an rnpact on the pilot's performancc. If so. a reduced
dut¡, pe nod should follow rhe reduced rest pe riod Ln order to comP€nsate for the possibility tiat
the pilot may' bc more susceptible to tirnc.since-au ake effects.
Required RecoverY Time
Complete recovery from a slecp debt may not oc.-ur after a single sleep period (Ca¡skadon &
Dernenr. 1979: Rosenthal et al.. l99l). Typicall\. two nighs of recover-r are required (Carskadon
& Demenr. l9?9: Kates er al.. 1970), atthough t-be required recovery P€nod may depend on the
lengrh of pnor *'aliefulness (Ca¡skadon & Dernent. 1982). Forexample, Kales et al. (1970 found
U te rat ure Ret ie¡
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