Background

Research pairing ecological momentary assessment (EMA) methodology and ambulatory cortisol during daily life is still rare, as is careful testing of the within-person associations between stress, affect, and cortisol. Using a circumplex approach, we considered both valence and arousal components of affect.

Purpose

To examine the within-person covariation of momentary cortisol with momentary perceived stress, affective valence, and affective arousal in everyday life.

Methods

115 working adults (Mage = 41.2; 76% women; 76% white) completed six EMA surveys per day over 3 days. Each assessment included reports of perceived stress and affect (used to construct indicators of affective valence and arousal), followed by a saliva sample (from which cortisol was assessed). Multi-level models were used to examine the momentary associations between perceived stress, affective valence, affective arousal, and cortisol.

Results

Moments characterized by higher perceived stress were associated with higher cortisol (p = .036). Affective valence covaried with cortisol (p = .003) such that more positive valence was associated with lower cortisol and more negative valence with higher cortisol. Momentary affective arousal was not related to cortisol (p = .131). When all predictors were tested in the same model, only valence remained a significant predictor of cortisol (p = .047).

Conclusion

Momentary perceived stress and affective valence, but not affective arousal, were associated with naturalistic cortisol. Cortisol was more robustly associated with affective valence than perceived stress or affective arousal. These findings extend our understanding of how moments of stress and particular characteristics of affective states (i.e., valence but not arousal) may "get under the skin" in daily life.

Abstract Background The role of coastal nutrient sources in the persistence of Karenia brevis red tides in coastal waters of Florida is a contentious issue that warrants investigation into the regulation of nutrient responses in this dinoflagellate. In other phytoplankton studied, nutrient status is reflected by the expression levels of N- and P-responsive gene transcripts. In dinoflagellates, however, many processes are regulated post-transcriptionally. All nuclear encoded gene transcripts studied to date possess a 5' trans-spliced leader (SL) sequence suggestive, based on the trypanosome model, of post-transcriptional regulation. The current study therefore sought to determine if the transcriptome of K. brevis is responsive to nitrogen and phosphorus and is informative of nutrient status. Results Microarray analysis of N-depleted K. brevis cultures revealed an increase in the expression of transcripts involved in N-assimilation (nitrate and ammonium transporters, glutamine synthetases) relative to nutrient replete cells. In contrast, a transcriptional signal of P-starvation was not apparent despite evidence of P-starvation based on their rapid growth response to P-addition. To study transcriptome responses to nutrient addition, the limiting nutrient was added to depleted cells and changes in global gene expression were assessed over the first 48 hours following nutrient addition. Both N- and P-addition resulted in significant changes in approximately 4% of genes on the microarray, using a significance cutoff of 1.7-fold and p ≤ 10-4. By far, the earliest responding genes were dominated in both nutrient treatments by pentatricopeptide repeat (PPR) proteins, which increased in expression up to 3-fold by 1 h following nutrient addition. PPR proteins are nuclear encoded proteins involved in chloroplast and mitochondria RNA processing. Correspondingly, other functions enriched in response to both nutrients were photosystem and ribosomal genes. Conclusions Microarray analysis provided transcriptomic evidence for N- but not P-limitation in K. brevis. Transcriptomic responses to the addition of either N or P suggest a concerted program leading to the reactivation of chloroplast functions. Even the earliest responding PPR protein transcripts possess a 5' SL sequence that suggests post-transcriptional control. Given the current state of knowledge of dinoflagellate gene regulation, it is currently unclear how these rapid changes in such transcript levels are achieved.

BACKGROUND AND OBJECTIVES: Although dispositional optimism and pessimism have been prospectively associated with health outcomes, little is known about how these associations manifest in everyday life. This study examined how short-term optimistic and pessimistic expectations were associated with psychological and physiological stress processes. METHODS: A diverse sample of adults (N = 300) completed a 2-day/1-night ecological momentary assessment and ambulatory blood pressure (ABP) protocol at ∼45-minute intervals. RESULTS: Moments that were more optimistic than typical for a person were followed by moments with lower likelihood of reporting a stressor, higher positive affect (PA), lower negative affect (NA), and less subjective stress (SS). Moments that were more pessimistic than typical were not associated with any affective stress outcome at the following moment. Neither optimism nor pessimism were associated with ABP, and did not moderate associations between reporting a stressor and outcomes. DISCUSSION: These findings suggest that intraindividual fluctuations in optimistic and pessimistic expectations are associated with stressor appraisals.

Repeated assessments in everyday life enables collecting ecologically valid data on dynamic, within-persons processes. These methods have widespread utility and application and have been extensively used for the study of stressors and stress responses. Enhanced conceptual sophistication of characterizing intraindividual stress responses in everyday life would help advance the field. This article provides a pragmatic overview of approaches, opportunities, and challenges when intensive ambulatory methods are applied to study everyday stress responses in "real time." We distinguish between three stress-response components (i.e., reactivity, recovery, and pileup) and focus on several fundamental questions: (a) What is the appropriate stress-free resting state (or "baseline") for an individual in everyday life? (b) How does one index the magnitude of the initial response to a stressor (reactivity)? (c) Following a stressor, how can recovery be identified (e.g., when the stress response has completed)? and (d) Because stressors may not occur in isolation, how can one capture the temporal clustering of stressors and/or stress responses (pileup)? We also present initial ideas on applying this approach to intervention research. Although we focus on stress responses, these issues may inform many other dynamic intraindividual constructs and behaviors (e.g., physical activity, physiological processes, other subjective states) captured in ambulatory assessment.

Introduction

Psychosocial factors are increasingly recognised as important determinants of cardiovascular disease risk. The North Texas Heart Study aims to understand the mechanisms responsible for this association with a focus on social vigilance (ie, scanning the environment for social threats). There is also growing interest in supplementing traditional methods (eg, survey assessment of psychosocial risk paired with cross-sectional and longitudinal health outcomes) with daily or repeated momentary assessment of psychosocial factors. However, there are relatively few longitudinal studies directly comparing these approaches with hard endpoints.

Methods and analysis

The North Texas Heart Study proposes a longitudinal measurement burst design to examine psychosocial determinants of subclinical atherosclerosis. A sample of 300 healthy community participants, stratified by age and gender, will complete survey measures, as well as 2 days of ecological momentary assessment at baseline and at a 2-year follow-up. A range of psychosocial and behavioural factors, objective biomarkers, as well as carotid intima-media thickness (cIMT) will be assessed at both time points. Unadjusted and adjusted models will evaluate cross-sectional associations and determinants of change in the cIMT.

Ethics and dissemination

The Institutional Review Board at the study coordinating institute (University of North Texas) has approved this study. Positive, negative or inconclusive primary and ancillary findings will be disseminated in scientific journals and conferences.

Although dispositional optimism and pessimism are associated with cardiovascular disease (CVD), their relative independence and unique contributions to CVD risk are unclear. This study addressed these issues by using multiple indicators of optimism and pessimism and linking them to objective risk factors for CVD. A diverse sample of adults (N = 300) completed baseline assessments (including global reports of optimism and pessimism), a 2-day/1-night EMA protocol with ambulatory blood pressure (BP) at 45-min intervals, and had inflammatory markers and carotid intima media imaging collected. EMA reports of momentary positive and negative expectations were averaged to form intraindividual (person) means of optimism and pessimism, respectively. Optimism and pessimism were only modestly correlated between- and within-assessment methods. Higher pessimism, regardless of assessment method, predicted both lower odds of whether BP dipping occurred and a smaller degree of dipping, but was unrelated to other biomarkers. Optimism was not uniquely predictive of CVD risk factors. Pessimism thus appears to exhibit stronger relative contribution to risk indicators of CVD than optimism.

Although stress is a common experience in everyday life, a clear understanding of how often an individual experiences and reports stress is lacking. Notably, there is little information regarding factors that may influence how frequently stress is reported, including which stress dimension is measured (i.e., stressors-did an event happen, subjective stress-how stressed do you feel, conditional stress-how stressful a stressor was) and the temporal features of that assessment (i.e., time of day, day of study, weekday vs. weekend day). The purpose of the present study was to conduct a coordinated analysis of five independent ecological momentary assessment studies utilizing varied stress reporting dimensions and temporal features. Results indicated that, within days, stress was reported at different frequencies depending on the stress dimension. Stressors were reported on 15-32% of momentary reports made within a day; across days, the frequency ranged from 42 to 76% of days. Depending on the cutoff, subjective stress was reported more frequently ranging about 8-56% of all moments within days, and 40-90% of days. Likewise, conditional stress ranged from just 3% of moments to 22%, and 11-69% of days. For the temporal features, stress was reported more frequently on weekdays (compared to weekend days) and on days earlier in the study (relative to days later in the study); time of day was inconsistently related to stress reports. In sum, stress report frequency depends in part on how stress is assessed. As such, researchers may wish to measure stress in multiple ways and, in the case of subjective and conditional stress with multiple operational definitions, to thoroughly characterize the frequency of stress reporting.