Physiological Activation as a Mediator in the Relationship Between Perseverative Cognition and Somatic Symptoms

Somatic symptoms are a significant medical and mental health concern that affects healthy adults and places a significant burden on healthcare systems. The perseverative cognition hypothesis posits that perseverative cognition results in prolonged physiological activation that may be interpreted as somatic symptoms. The purpose of this study was to further examine this hypothesis in a sample of young adults. First, I hypothesized that perseverative cognition would prospectively predict somatic symptoms after controlling for anxiety and depression. Second, I hypothesized that parasympathetic nervous system functioning, measured as respiratory sinus arrhythmia (RSA) and sympathetic nervous system functioning, measured as electrodermal responding (EDR) would mediate this relationship. RSA and EDR were measured before, during, and after a stressor task to provide measures of basal levels, reactivity to the stressor, and recovery from the stressor respectively. These hypotheses were tested in a sample of 220 young adults. Participants ranged from 18 to 39 years old (M = 19.63, SD = 12.10), 84.5% of the participants were female, and 65.5% were Caucasian. Perseverative cognition predicted somatic symptoms in the unexpected direction in both hypothesized models (RSA: β = -0.23, p = 0.001; EDR: β = -0.23, p = 0.074). When anxiety and depression were removed as covariates, somatic symptoms were significantly predicted by perseverative cognition in the expected direction in both models (RSA: β = 0.38, p \u3c 0.001; EDR: β = 0.37, p = 0.003). Neither RSA nor EDR at any time point were significantly related to either perseverative cognition or somatic symptoms, and no indirect effects were observed. Individual mediations revealed that RSA recovery significantly predicted somatic symptoms (β = 0.16; p = 0.029) such that individuals whose parasympathetic nervous system re-engaged following the stressor experienced a higher level of somatic symptoms. Additionally, individuals who reported higher levels of perseverative cognition experienced greater increases in EDR during the stressor task (β = 0.17; p = 0.041). Overall, the findings of this study suggest that perseverative cognition is related to sympathetic nervous system functioning, while parasympathetic nervous system functioning is related to reporting of somatic symptoms. Future research directions and clinical implications are discussed

Effects of mindful physical activity on perceived exercise exertion and other physiological and psychological responses: results from a within-subjects, counter-balanced study

BackgroundMost adults are insufficiently active. Mindfulness training may increase moderate to vigorous physical activity (MVPA) adoption and adherence. However, physiological and psychological factors underlying these effects are not well understood. This study examined the effects of an acute bout of MVPA, mindfulness training, and combined MVPA and mindfulness training on physiological and psychological outcomes.MethodsHealthy adults (N = 29, Mage = 28.6) completed 20-min counterbalanced conditions: (a) mindfulness training (MIND); (b) moderate intensity walking (PA), and (c) moderate intensity walking while listening to MVPA-specific guided mindfulness training (PAMIND). Heart rate (HR), Rating of Perceived Exertion (RPE), Feeling Scale (FS) and Blood Pressure (BP) were measured at rest, at regular intervals during each condition, and post-condition. Mindfulness, state anxiety, and self-efficacy were assessed pre- and post-condition.ResultsAverage and peak HR, systolic BP (SBP), and RPE were significantly higher, and average and peak FS were significantly lower during the PA and PAMIND conditions compared to MIND (p < 0.001). Average RPE was significantly higher for PA compared to PAMIND (p < 0.001). Heart rate, feeling scale, body and mental events mindfulness, and self-efficacy for walking increased from pre to post (all p’s < 0.001) for all conditions. Time by condition interactions were significant for change in heart rate, mental events mindfulness, and state anxiety from pre- to post-condition.ConclusionThe physiological response to MVPA and PAMIND were similar. However, RPE was rated lower in the PAMIND condition, which could have implications for MVPA adoption and maintenance. Future work should further explore RPE combining MVPA and mindfulness training

Cognitive Mechanisms Reciprocally Transmit Vulnerability between Depressive and Somatic Symptoms

Despite high comorbidity between depressive and somatic symptoms, cognitive mechanisms that transmit vulnerability between symptom clusters are largely unknown. Dampening, positive rumination, and brooding are three cognitive predictors of depression, with rumination theoretically indicated as a transdiagnostic vulnerability through amplifying and diminishing affect in response to events. Specifically, the excess negative affect and lack of positive affect characteristic of depressive symptoms and underlying somatic symptoms may cause and be caused by cognitive responses to events. Therefore, the current study examined whether comorbidity between depressive and somatic symptoms may be explained by the cognitive mechanisms of dampening and positive rumination in response to positive events and brooding in response to negative events among adults (N=321) across eight weeks of assessment. We hypothesized that greater dampening and brooding would reciprocally predict greater depressive and somatic symptoms, while greater positive rumination would reciprocally predict fewer depressive and somatic symptoms. Mediation analyses in AMOS 22 indicated that dampening and brooding mediated reciprocal pathways between depressive and somatic symptoms, but positive rumination did not. Findings propose dampening and brooding as mechanisms of the reciprocal relationship between depressive and somatic symptoms through diminishing positive affect and amplifying negative affect in response to positive and negative events

Hydrolyzable Poly(β‐thioether ester ketal) Thermosets via Acyclic Ketal Monomers

Hydrolytically degradable poly(β-thioether ester ketal) thermosets are synthesized via radical-mediated thiol-ene photopolymerization using three novel dialkene acyclic ketal monomers and a mercaptopropionate based tetrafunctional thiol. For all thermoset compositions investigated, degradation behavior is highly tunable based on the structure of the incorporated ketal and pH. Complete degradation of the thermosets is observed upon exposure to acidic and neutral pH, and under high humidity conditions. Polymer networks composed of cross-link junctions based on acyclic dimethyl ketals degrade the quickest, whereas networks containing acyclic cyclohexyl ketals undergo hydrolytic degradation on a longer timescale. Thermomechanical analysis reveals low glass transition temperatures and moduli typical of thioether-based thermosets