Brief Report Sympathetic and Parasympathetic Responses to Social Stress across Adolescence ABSTRACT: Many transformations that occur in adolescence are related to emo- tion and emotion regulation, yet very little is known about the autonomic under- pinnings of these changes. The aim of the study was to document age-related differences in autonomic responses to social stress and relations to emotion regu- lation. Ninety-nine female adolescents engaged in a paced breathing and a spon- taneous speech task while electrocardiography measurements were taken. Spectral decomposition of the heart period data was used to create measures of sympathetic and parasympathetic activity. Results revealed a positive correlation between age and sympathetic activity and a negative correlation between age and parasympathetic activity. These findings contribute to a better understanding of the age-related norms of cardiac variability across adolescence. ß 2011 Wiley Periodicals, Inc. Dev Psychobiol Keywords: respiratory sinus arrhythmia; sympathetic and parasympathetic activity; adolescence; suppression; heart rate variability; social stress INTRODUCTION There is an emerging understanding of the associations between heart rate variability (HRV), due to both para- sympathetic and sympathetic influence, and individual differences in emotional functioning. Low levels of resting respiratory sinus arrhythmia (RSA), for example, have been consistently associated with dys- functional emotional traits, such as aggression (Gordis, Feres, Olezeski, Rabkin, & Trickett, 2010), anxiety (Watkins, Grossman, Krishnan, & Sherwood, 1998), and depression (Carney et al., 1995). These HRV– emotion connections have been mostly examined in infants (Stifter, Fox, & Porges, 1989), preschoolers (Fabes, Eisenberg, & Eisenbud, 1993), and adults (Dywan, Mathewson, Choma, Rosenfeld, & Segalowitz, 2008), and most often as comparisons of atypical groups to controls (Dishman et al., 2000). As a result, typical changes in HRV across wide age ranges and corresponding emotional associations are not as well understood. In particular, changes in stress, emotional reactivity, and regulation that typically occur during adolescence (e.g., Hollenstein & Lewis, 2006; Larson & Ham, 1993) have rarely been examined in terms of the sympathetic and parasympathetic dynamics that are most likely involved. Hence, the purpose of the present study was to document typical age-related differences in HRV across adolescence and examine the relation- ship of these age differences with strategies employed to regulate stressful emotional states. Tonic and Phasic HRV The two branches of the autonomic nervous system (ANS), the sympathetic (SNS), and parasympathetic (PSNS), are a coordinated response system underlying arousal, stress, and flight/fight behavior (Porges, 1992), as well as emotions (Levenson, Ekman, & Friesen, 1990). The most obvious manifestations of ANS func- tioning are changes in the length of the cardiac cycle over time (i.e., HRV; Grossman, Van Beek, & Wientjes, 1990) that underlie stress responses. HRV can be Developmental Psychobiology Tom Hollenstein 1y Adrian McNeely 1 Jenny Eastabrook 1 Allison Mackey 1 Jessica Flynn 2 1 Department of Psychology Queen’s University at Kingston 220 Craine Hall, Ontario Canada K7L 3N6 E-mail: tom.hollenstein@queensu.ca 2 Kent State University at Kent Kent, OH Received 4 August 2010; Accepted 27 May 2011 y Assistant Professor. Correspondence to: T. Hollenstein Contract grant sponsor: Canadian Foundation for Innovation; Contract grant sponsor: Queen’s University; Contract grant sponsor: Social Sciences and Humanities Research Council. Published online in Wiley Online Library (wileyonlinelibrary.com). DOI 10.1002/dev.20582 ß 2011 Wiley Periodicals, Inc.