The authors examined the relationships between family caregivers' construal of their preillness affection for and cohesiveness with an Alzheimer's disease (AD) patient and subsequent cardiovascular functioning. Scale validation demonstrated the psychometric properties. In a study conducted 2 years later, 31 family caregivers of AD victims performed stress-inducing tasks while cardiovascular activity was monitored. Path analyses revealed that caregivers relatively high in preillness affection for the AD patient were characterized by lower heart rate reactivity and resting diastolic blood pressure. In contrast, caregivers relatively high in preillness cohesion were characterized by higher resting systolic and diastolic blood pressure. These results suggest that caregivers' social relationships may play an important, although not always beneficial, role in cardiovascular regulation and health.