Julia O'BRyan

Conflicts with close others and subsequent affective reactions can have long-term consequences for mental and physical health. Building on recent studies using transcutaneous vagus nerve stimulation (tVNS) highlighting the role of the vagus nerve in social functioning, we examined if tVNS can modulate the emotional, physiological, and behavioral responses to a romantic conflict. Romantic couples (N_couples= 67; N_individuals= 134) were randomly assigned to tVNS or sham stimulation. Both partners received continuous tVNS or sham stimulation for 15 min before and during a six-minute discussion about a recurring conflict topic. We examined each partner's emotional and respiratory sinus arrhythmia (RSA) reactivity to conflict and the partners' physiological and behavioral attunement to each other. Our results revealed no condition differences in emotional experiences, but individuals receiving tVNS (vs. sham stimulation) experienced greater decreases in RSA during conflict. Further, while RSA reactivity synchrony did not differ between conditions, couples in the tVNS (vs. sham stimulation) condition showed greater behavioral synchrony. This work provides experimental evidence supporting the role of the vagus nerve in modulating reactions to stressful social interactions, highlighting the potential of tVNS to subtly influence couple dynamics at physiological and behavioral levels.

Background: To cope with chronic stress, which can contribute to depression, humans often pursue arousal-reducing activities. Yet, hormetic stressors (intermittent, acute stressors) might also reduce chronic stress. Purpose: We compared the effects of arousal-reducing and arousal-enhancing interventions on depressive symptoms and perceived stress. Methods: Female adults (N = 141; predominantly White, 63%, and Asian, 34%) reporting high perceived stress were randomized to 1 of 4 three-week stress resilience interventions in 2019-2020. Low arousal conditions included mindfulness meditation or slow breathing with warm showers (Control). Hormetic stress conditions included fast paced breathing with cold showers (the Wim Hof Method; WHM) or high-intensity interval training. We assessed depressive symptoms and perceived stress at baseline, postintervention, and 3 months later, and cortisol reactivity to a lab stressor. Results: At postintervention, all 4 groups had decreases in depressive symptoms (15.93% reduction, r = .76, P < .001) and perceived stress (9.70% reduction, r = .48, P < .001), with no group differences. “As treated” analysis showed the WHM group had better maintenance of reduced depression 3 months later (r = .17, P < .01). The WHM group had greater increases in daily positive affect across days (r = .16, P ≤ .05) and at postintervention (r = .17, P < .015) compared to the control group. Groups were similar in cortisol reactivity pre- and postintervention. Conclusions: All groups experienced reduced stress and depressive symptoms and did not differ from each other after 3 weeks. After 3 months, a post hoc analysis of adherent subjects showed the WHM group had more sustained improvements in depression and positive affect, a finding that needs replication with larger and more diverse samples.

Paced breathing-longer exhalation than inhalation-can show short-term improvement of physiologic responses and affective well-being, though most studies have relied on narrow sample demographics, small samples, and control conditions that fail to address expectancy effects. We addressed these limitations through an app-based experiment where participants were randomly assigned to paced breathing or sham control (hand closure) conditions. We first validated the conditions in an online sample (N = 201; Study 1) and in a lab environment (N = 72; Study 2). In the primary app-based experiment, participants (N = 3,277; Study 3) completed 3 days of baseline assessments that included three check-ins each day in which we obtained heart rate and blood pressure responses using an optic sensor and assessed current stress and emotions. Participants were then randomly assigned to either the paced breathing or hand closure condition for the next 6 days. Relative to baseline days, both conditions were associated with increased positive emotions and perceived coping, and reduced blood pressure. Moreover, the increase in positive emotions and perceived coping was not evident among a comparison sample (N = 2,600) who completed check-ins but did not participate in either of the paced breathing or sham-control conditions. However, their blood pressure declined over time, suggesting that the continual monitoring of one's blood pressure may result in detectable decreases. Our results highlight the importance of designing experiments with appropriately matched control conditions and suggest that changes associated with techniques like paced breathing, in part, may stem from positive incidental features of the technique. (PsycInfo Database Record (c) 2024 APA, all rights reserved).