A review paper on loneliness by Eoin Brown, Dr. Stephen Gallagher and Dr. Ann-Marie Creaven features in the latest issue of Psychophysiology (May 2018). This paper was supported by funding from the Irish Research Council.
Brown, E. G., Gallagher, S., & Creaven, A.M. (2018). Loneliness and acute stress reactivity: A systematic review of psychophysiological studies. Psychophysiology, 55(5) https://doi.org/10.1111/psyp.13031
Loneliness has a negative impact on health, but exactly how this occurs is still not fully understood. Stress reactivity is one biological mechanism that is potentially influenced by loneliness. The purpose of the review was to examine the existing research on the relationship between loneliness and acute stress reactivity.
Overall, the findings suggest that loneliness is associated with atypical physiological reactivity to stress. Higher levels of loneliness were related to exaggerated blood pressure and inflammatory reactions. For cardiac (e.g., heart rate), cortisol and immunity measures, there was some evidence suggesting that loneliness was linked to diminished/blunted responses in these outcomes. This is important as dysregulation in how individuals respond to stress (either too high (exaggerated) or too low (blunted) can be harmful.
This suggests that stress reactivity could be one of the biological mechanisms through which loneliness impacts upon health.