4 - SLEEP AND HEALTH
Sleep in Medical Conditions
a variety of common medical illnesses—including
adult and juvenile arthritis , asthma , cancer , cardiopulmonary
diseases, chronic fatigue syndrome (CFS), diabetes , end-stage
renal disease (ESRD ), fibromyalgia (FM) , human immunodeficiency
virus (HIV ), irritable bowel syndrome (IBS), obesity , and
temporomandibular joint disorders (TMJD) — frequently experience
sleep disturbances. It is recognized that medical illnesses
can adversely affect sleep quality , and that pain , infection,
and inflammation can induce symptoms of excessive daytime sleepiness
and fatigue. It is less clear, however, how sleep quality affects
disease progression and morbidity. In addition, patients with
these medical illnesses may also have a primary sleep disorder
(see Section V) that further contributes to significant morbidity.
The role of sleep disturbances and sleep disorders in the morbidity
of most chronic conditions is understudied in children and
adults and, as a result, is poorly understood. Similarly, how
sleep disturbances affect responses and adherence to medical
therapy for the primary illness and the best ways to manage
disturbed sleep in most chronic conditions is understudied.
The relationship between sleep processes and the development,
progression, and management of chronic diseases, therefore,
requires further study.
with abnormal sleep architecture is most evident in disorders
characterized by known structural pathology, e.g., arthritis
, cancer , heart failure, and ESRD. In chronic pain-related
conditions without known structural pathology (e.g., FM,
CFS, IBS), the most striking observation in these “unexplained
disorders”, is a self-report of poor and nonrestorative sleep
that is often out of proportion to modest changes in objective
measures of sleep. This discrepancy between subjective and
objective sleep indicators has been studied extensively in
FM and is most evident when patients are selected on the basis
of appropriate case definition, compared to women of similar
age, and screened for psychiatric disorders, particularly depression
. Insomnia in these chronic conditions is known to exacerbate
symptoms of pain, fatigue , and daytime sleepiness , negatively
impact work performance, social and family relationships, quality
of life , and increase use of health care services. Controversy
still exists, however, regarding the clinical significance
and diagnostic value of abnormal sleep physiology in these
Sleep is considered
restorative and important for illness recovery. It remains
unknown, however, whether sleep actually facilitates recovery
processes. Clinicians advise patients to “get plenty of sleep” during an acute febrile illness or
following surgery or trauma , but sleep is often fragmented
and disrupted. These sleep disturbances are considered “incident” or “transient” forms
of insomnia that are treated readily with hypnotic medications
and often resolve with recovery. However, mutually exacerbating
effects of disturbed sleep and primary illness may be a significant
barrier to full recovery. The role of acute illness-related
insomnia in the development and pathogenesis of chronic conditions
both in children and adults is understudied and perhaps underestimated.
In addition, the impact of acute care environments in exacerbating
sleep disruption and further limiting successful implementation
of medical or behavioral regimens is understudied.
Progress in the Last 5 Years
and other pulmonary diseases commonly exacerbate during sleep,
but the mechanisms involved are poorly understood.
is an association between daytime sleepiness and cardiovascular
disease-related morbidity and mortality (e.g., hypertension
, myocardial infarction, and congestive heart failure ).
of diabetes is directly associated with severity of distur
bed sleep, and partial sleep deprivation of healthy adults
increases insulin resistance .
with ESRD have disrupted nocturnal sleep with excessive daytime
sleepiness and the timing of dialysis treatment affects mortality.
ESRD patients on dialysis have among the highest incidence
of both SDB and periodic leg movements (PLMs) in sleep, and
PLMs are a significant predictor of survival and mortality
in this population.
disturbance and fatigue are highly prevalent and disabling
symptoms in a majority of individuals infected with HIV .
Recent findings suggest that symptoms of sleep disturbance
and fatigue are independently associated with survival among
people with HIV infection. However, sleep disturbances in children
and adults with HIV remains understudied, underdiagnosed, and,
“Unexplained disorders” are
more prevalent in females than in males, but the biologic
basis of this sex difference is poorly understood. Failure
to identify a structural basis for these disorders has led
some researchers and clinicians to embrace sociocultural
explanations that can bias research and care.
timing and reduced nocturnal concentrations of sleep-dependent
hormones (e.g., growth hormone, prolactin , melatonin ) have
been described in a number of chronic conditions and are
possibly linked with altered sleep physiology and reduced
of altered circadian rhythms observed in FM patients coupled
with lower concentrations of sleep-dependent hormones (growth
hormone and prolactin ) in other studies, underscores the
possibility of dysfunctional homeostatic sleep regulation
as a basis for symptoms of poor sleep and fatigue .
is a major factor associated with disrupted sleep in many
chronic conditions. Experimental studies in healthy young
men and in animals show reduced responsiveness to noxious
stimuli during sleep, but the mechanisms involved in sleep-related
pain modulation are unknown.
studies have identified areas of the thalamus and basal ganglia
that may be hypofunctional in women with FM and hence may
contribute to abnormal sleep physiology.
the United States ' population ages, the number of people
living with chronic medical illnesses will increase dramatically
in the next two decades. It will be important to identify
chronically ill populations at highest risk for sleep disturbances,
determine the factors most associated with disturbed sleep,
and the best ways to improve such sleep disturbances. There
is also a need to understand how sleep disturbances affect
adherence to treatments for chronic disease and ways that
improving sleep may improve treatment outcomes.
the bidirectional relationship between sleep processes and
disease development, progression, and morbidity. Determine
identifiable, measurable characteristics of sleep quality
that could serve as potential indicators of primary disease
diagnosis, progression, and severity. Such markers might
indicate how sleep regulation and timing are reciprocally
coupled to disease pathophysiology.
and clinical research is needed in children and adults to
elucidate the benefits of sleep, the risks associated with
insufficient sleep during an acute illness, and the extent
of unresolved acute illness-related insomnia. The beneficial
outcomes associated with improved sleep during illness using
behavioral , pharmacological, and environmental approaches
need to be explored.
interdisciplinary basic science studies of the effects of
pain and inflammation on sleep physiology both in animals
and in humans.
experimental challenge studies using sleep delay or partial
sleep deprivation to assess the extent of homeostatic sleep
regulation dysfunction in chronic illnesses.
sleep, neuroendocrine and autonomic functioning in newly diagnosed patients with FM compared to patients
with CFS and with primary insomnia. Studies of children, adolescents,
and young women should be particularly informative.
patients with chronic illness, determine the effectiveness
of self-management strategies (e.g., cognitive -behavioral
and sleep hygiene) designed for treating primary insomnia,
in relieving symptoms and improving clinical outcomes.