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Abstract:
For decades, researchers have examined endocrine and heart
rate measures in child research to assess
hypothalamic-pituitary-adrenocortical and autonomic activity in
response to stress. More recently, research has attempted to
abstract the separate influences of the parasympathetic, through
measures of Vagal Tone (VT), and sympathetic nervous systems,
through measure of Pre-Ejection Period (PEP), on the cardiac stress
response. By analyzing both PEP and VT, work on adults has shown
that some individuals increase heart rate by lifting or reducing
VT, while others do so by increasing sympathetic tone, while still
others may do both. Those who achieve similar increases in heart
rate but do so primarily by sympathetic regulation are also the
ones who are more emotionally anxious, elevate cortisol more, and
experience more stress related health problems. The current study
examined the physiological correlates (heart rate, PEP, VT, and
cortisol) of reactivity to a standard psychological stress test,
the Trier Social Stress Test for Children in 8- and 9-year old
girls. Physiologic measures revealed individual differences in
girls responses to the test. Approximately half of the girls
responded to the stressor of entering the laboratory and these two
groups differed in HR , PEP, and VT reactivity, as well as
temperamental dimensions. Being the first to examine the
relationship between such measures in children, this study further
supports the importance of examining multiple systems
simultaneously in developing populations.
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