PROJECT ABSTRACT
Loneliness is defined as a discrepancy between one's desired and actual level of social connection. Loneliness
as a construct captures more than social isolation; it captures emotional isolation. Reported loneliness is a
consistent predictor of increased rates of morbidity and mortality. Current estimates equate loneliness as
having the same impact on mortality as smoking approximately 15 cigarettes a day. One pathway by which
loneliness may impact mortality is through an increased risk of cardiovascular disease (CVD). Studies routinely
find a connection between loneliness and CVD, but the mechanism of that pathway is unclear. One factor
common to both loneliness and CVD that may explain the relationship is the engagement of the sympathetic
(SNS) and parasympathetic nervous systems (PNS). The PNS slows heart rate and reduces physiological
arousal. The SNS is activated during times of threat, increasing heart rate and oxygen flow in the body. High
levels of SNS engagement have been implicated as having a causal role in the development of CVD.
Consistent with this proposed pathway, lonely individuals have lower respiratory sinus arrhythmia at rest and
during stressors than non-lonely individuals, an indicator of increased SNS and lower PNS activity. This
nervous system engagement may also be involved in disruptions in the behavioral processes that lead to
connection. Social connection occurs one member of a dyad engages in a vulnerable self-disclosure, and the
other responds in an understanding/caring way. Researchers have hypothesized that in lonely individuals, the
SNS may be easily activated to regulate physiology and behavior, producing a lack of disclosure or inadequate
responsiveness to disclosure. This pattern of SNS engagement and disruption to the social connection process
may result in loneliness and increase the risk of CVD through the excessive engagement of the SNS. The
present study proposes an innovative design using multiple ambulatory assessment techniques to assess
heart rate variability (HRV), a biomarker of SNS engagement, during social interactions. During waking hours,
participants will wear a heart rate variability collection device. Additionally, participants will complete both
signal and event contingent ambulatory assessment surveys detailing their most recent social interactions and
current feelings of loneliness. This project represents the first step of a line of research with the long-term goal
of mitigating the effect of loneliness on CVD through psychosocial intervention. That is to say, the proposed
study will inform psychosocial prevention strategies for CVD resulting from loneliness. The project moves
towards that goal by identifying the relationship between closeness-generating behaviors and biomarkers of
CVD and clarifying what part of the connection-building process is interrupted in lonely individuals.