Loneliness and the heart : examining the associations between trait loneliness, state loneliness, and high-frequency heart rate variability

Loneliness is a recognized risk factor for numerous adverse health outcomes, including early death. However, state loneliness may also be evolutionarily adaptive by signaling our social connection to others is at risk and motivating social reaffiliation. Long-term and short-term changes in vagal parasympathetic functioning may represent a mechanism by which both detrimental and beneficial effects of loneliness impact human physiology. The present study investigates the differential influences of trait loneliness and state loneliness on high-frequency heart rate variability (HF-HRV), an index of vagal parasympathetic activity. In controlled laboratory settings, HF-HRV in young women (N = 148) was monitored before, during, and after a cognitive challenge task, as well as before, during, and after an induction of state loneliness. Replicating and extending prior research, higher trait loneliness predicted blunted HF-HRV reactivity to cognitive demand, controlling for covariates. Higher trait loneliness also predicted blunted HF-HRV recovery following cognitive demand, although this appeared to be a function of initial blunted HF-HRV reactivity among the chronically lonely. Consistent with the evolutionary theory of loneliness, acute state loneliness was associated with increased HF-HRV above baseline levels, regardless of self-reported trait loneliness. During recovery from state loneliness, trait loneliness predicted change in HF-HRV, such that HF-HRV decreased in high trait-lonely women, whereas HF-HRV increased in low trait-lonely women. The current findings indicate that trait loneliness is associated with a potentially maladaptive physiological response to cognitive demand. The study also provides the first evidence of increased vagal parasympathetic activity during acute state loneliness, a potential indication of a physiological state conducive to social engagement behaviours. The findings further suggest that physiological capacity for social engagement may differ as a function of trait loneliness, immediately following an acute experience of loneliness. Finally, the utility of a robust loneliness induction paradigm developed from existing methods was demonstrated, supporting its application in future research seeking to disentangle trait and state loneliness.Arts, Faculty ofPsychology, Department ofGraduat