A Randomized Controlled Trial of a Mindfulness-Based Weight Loss Intervention on Cardiovascular Reactivity to Social-Evaluative Threat Among Adults with Obesity.

Abstract

Mindfulness-based interventions have been found to reduce psychological and physiological stress reactivity. In obesity, however, stress reactivity is complex, with studies showing both exaggerated and blunted physiological responses to stressors. A nuanced view of stress reactivity is the "challenge and threat" framework, which defines adaptive and maladaptive patterns of psychophysiological stress reactivity. We hypothesized that mindfulness training would facilitate increased challenge-related appraisals, emotions, and cardiovascular reactivity, including sympathetic nervous system activation paired with increased cardiac output (CO) and reduced total peripheral resistance (TPR) compared to a control group, which would exhibit an increased threat pattern of psychophysiological reactivity to repeated stressors. Adults (N=194) with obesity were randomized to a 5.5-month mindfulness-based weight loss intervention or an active control condition with identical diet-exercise guidelines. Participants were assessed at baseline and 4.5 months later using the Trier Social Stress Task. Electrocardiogram, impedance cardiography, and blood pressure were acquired at rest and during the speech and verbal arithmetic tasks to assess pre-ejection period (PEP), CO, and TPR reactivity. Mindfulness participants showed significantly greater maintenance of challenge-related emotions and cardiovascular reactivity patterns (higher CO and lower TPR) from pre to post-intervention compared to control participants, but groups did not differ in PEP. Findings were independent of changes in body mass index. Mindfulness training may increase the ability to maintain a positive outlook and mount adaptive cardiovascular responses to repeated stressors among persons with obesity though findings need to be replicated in other populations and using other forms of mindfulness interventions.