Protective Role of Sustained Positive Emotions in Mitigating Negative Mood Responses Following Acute Laboratory Stressor in Middle-Aged and Older Dementia Caregivers.

Positive emotions can buffer stress-related negative emotions; however, it remains unclear whether such protective benefits extend to middle-aged and older adult caregivers of family members with dementia, a population particularly vulnerable to stress and its health consequences. This secondary analysis of laboratory data from a parent clinical trial (R01AG049764) examined the role of sustaining positive affect in buffering the effects of stress-related emotional reactivity on subsequent negative mood. This study recruited 192 cognitively healthy, middle-aged, and older adults who were dementia caregivers (mean age = 68.14) reported high stress and/or caregiver burden. During a laboratory session, emotional reactivity to an acute stressor (a math and working memory task) was assessed using changes in valence and arousal from the Self-Assessment Manikin (SAM) before and after the stressor. Positive and Negative Affect Schedule (PANAS) was completed 10 min before and 40 min after stressor task. Hierarchical regression models tested whether the changes of positive affect across the session moderated associations between SAM valence/arousal reactivity to the stressor and later negative mood. As hypothesised, greater negative valence and arousal reactivity to acute stressor were each associated with higher negative mood later. Among caregivers with less decline in positive affect across session, associations between valence/arousal reactivity and later negative mood were weakened. Our findings support the undoing hypothesis, demonstrating that maintaining positive affect mitigates the impact of emotional reactivity on negative mood. This suggested that interventions fostering sustained positive emotions may be a promising strategy to enhance caregivers' stress adaptation and promote healthier ageing.