Page 506 - Encyclopedia of Nursing Research

Sleep SCIenCe n 473

or environmental interference factors) but report negative impressions, indiscrimi-
is most troublesome when enduring or fre- nately. moreover, perceptions of sleep do not
quent (referred to as chronic and potentially always match physiological indicators, mak- S
related to an inherent propensity toward ing interpretation of the factors influencing
enhanced arousal). Insomnia includes fea- sleep complex and dependent on how sleep
tures of difficulty falling asleep, waking up quality is assessed.
often during usual sleep episodes, or prema- Knowledge about sleep comes from
ture awakening with inability to fall back to a variety of research approaches. experi-
sleep. environmentally, good quality sleep mentally and mainly using animal models,
(pattern and duration) is most evident when physiological sleep/wake regulation and
sleep is initiated on the decline of the circa- genetics are studied. epidemiologically,
dian body temperature curve during grow- sleep patterns are studied across popula-
ing environmental darkness and when sleep tions in the context of culture, age, or gender.
episodes occur consistently over the same Descriptively, studies are done to understand
span of hours on the 24-hour light–dark the function of and need for sleep and to
cycle. Behaviorally, good quality sleep is gain insights into factors predictive of poor
promoted by sleep initiation after a prepara- sleep. many studies are done in the context of
tion ritual and in a relaxed and drowsy state. conditions thought to be stressful, for exam-
Sleep is seen to become less stable with age, ple, disease, illness, pregnancy, menopause,
leading to more frequent awakenings during relocation, or environmental catastrophes.
the night, which are problematic only if sleep nursing scientists most often seek to under-
is difficult to resume. stand how sleep, or more precisely sleepless-
Sleep can be assessed physiologically ness, is related to disease and illness, what
using polysomnography (i.e., brainwave, can be done to promote sleep and how sleep
muscle tension, and eye movement activ- is affected by environments and life contexts.
ity monitoring) to reveal a series of stages Sleep science generated by nursing sci-
and patterns, or by body activity monitors entists largely is built on the premise that
that distinguish sleep from waking. Sleep personal stress, disease/illness, and sleep/
also can be assessed behaviorally (by direct wake quality are interactive. The notions that
observation) or by self-reported perceptions illness/disease and hospitalization/insti-
(retrospective recall or global impressions tutionalization interfere with usual sleep/
as histories or concurrent reporting in dia- wake behavior are prominent. For example,
ries or logs). Somnographically, sleep is seen nursing scientists have developed programs
to begin with transitional signs, progressing of sleep research in the context of renal fail-
into a light stage then into deep (slow wave) ure (parker, Bailey, Rye, Bliwise, & Van
sleep, followed by a period of rapid eye Someren, 2008), heart failure (Redeker, 2008),
movement sleep to complete one sleep cycle, cancer (Berger, 2009), sleep apnea treatment
taking about 60 to 90 minutes. Consequently, adherence (Weaver & Sawyer, 2010), juvenile
a full night of sleep consists of three to six arthritis (Ward et al., 2010), and fibromyalgia
cycles, depending on total sleep duration. (landis, lentz, Tsuji, Buchwald, & Shaver,
Various sleep measures have limitations, 2004) or have expanded research to include
including physiological measures that are sleep, for example, with functional bowel
time consuming, require expensive technol- disorders (heitkemper, et al., 2005). In addi-
ogy, and have the potential to interfere with tion, evident are programs of nursing science
natural sleep. Behavioral observations are research related to women’s reproductive
tedious, time consuming, and potentially status transitions in which sleep changes
inaccurate. Self-report methods are subject are known to manifest, for example (lee,
to preferred answers and the propensity to Baker, newton, & Ancoli-Israel, 2008), during