Study Shows How Stress may Affect Sleep Patterns
Although the link between a stressful day and a
restless night is well known, scientists are still
researching the exact ways that stress affects
sleep. A new study suggests that stress may disrupt
the nervous system's natural rhythms during various
Stressed sleepers experience more arousal during
sleep, Martica Hall, Ph.D. of the University of
Pittsburgh and colleagues write in the journal
Sleepers who were less relaxed during sleep also
woke up more often and had fewer episodes of deep
sleep, according to the researchers.
Hall and colleagues measured the central nervous
system changes by monitoring heart rate variations
59 healthy volunteers. Certain heart rate variations
act as indirect glimpses into the activity of the
involuntary nervous system, which directs the
function of organs like the heart and lungs.
"Changes in heart period variability associated with
acute stress may represent one pathway to disturbed
sleep," Hall says. The researchers examined the link
between stress and sleep in 59 healthy
undergraduates. To trigger stress in some of the
volunteers, half of the students were told that they
would deliver a 15-minute speech upon awakening. The
topics were to be chosen for them in the morning.
Heart rate variability differed significantly
between the stressed and non-stressed groups. The
stressed group had changes in heart rate patterns
during non-REM and REM sleep.
Insomniacs have heart rate variability patterns
similar to those seen in the stressed students,
which may suggest that similar pathways of nervous
system disruption are at work in the disorder,
according to Hall and colleagues.