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ROGER ROSA |
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What Can The Study Of Work Scheduling Tell Us
About Adolescent Sleep?
ROGER ROSA, Ph.D  ield studies of work scheduling have
demonstrated a reliable association between
working hours, sleep quantity and quality, and
waking alertness. Both the circadian timing of
working hours, and the number of hours worked
in a day or week, can affect sleep and
alertness. With respect to circadian timing,
sleep will be affected adversely to the degree
to which working hours intrude upon the normal
nighttime sleeping hours. This tendency is
most obvious in night shift workers who must
sleep during the daytime, but also is quite
apparent in those individuals who begin work
before 7:00 am. Questionnaire studies have
suggested that sleep often is truncated in
these workers because of the necessity of
early-morning awakening combined with
circadian rhythm and social limitations on
retiring early in the evening. A recent NIOSH
study will be presented to support these
claims. That study demonstrated that a
one-hour delay in morning shift start times
increased worker sleep and improved waking
alertness during the shift.
Sleep also is curtailed when the total number of working hours is increased in a day or across the workweek. A series of NIOSH studies of 12-hour shift schedules will be presented to demonstrate both a gradually accumulating sleep debt over a 4-day work week, and decreased worker alertness during the 12-hour shifts. This sleep debt can be attributed partially to reduced daily personal time afforded by the extended workdays, which results in sleep being sacrificed for the sake of social/domestic obligations.
Studies of work scheduling in adults have
direct relevance to adolescents because young
people have the 'job' of attending and
performing well at school on a schedule
similar to the 40-hour adult workweek. In
addition, at least half of U.S. adolescents
are part of the commercial workforce, which
can add up to 20 additional hours to their
workweek. It is clear, in this context, that
the study of extended workdays in adults has
direct application to adolescents having a 50-
to 60-hour weekly school-work schedule.
Studies of extended workdays in adults suggest
that sleep loss increases in proportion to the
number of scheduled work hours per week, which
could place working adolescents at greater
risk of poor school performance or having an
accident or injury. Studies of adult workshift
timing also are relevant, however, since
adolescents often are required to begin school
very early in the morning because of
transportation limitations. Consequently, they
may have truncated morning sleep and
associated waking drowsiness similar to adult
morning shift workers. Research into the
degree to which these effects differ in adults
versus adolescents is not substantial. Recent
evidence suggests that adolescents have a
greater sleep need than adults which could
exacerbate the effects of work-related sleep
debt. Young people, however, usually have
fewer domestic duties than adults which could
allow greater opportunity for sleep. The
modulating effects on adolescents of other
work-related fatigue factors, such as
workload, pacing, or environmental exposures,
generally are unknown.
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