While it is not too difficult to imagine that loneliness has mental health effects, it may be more surprising that loneliness has physical health effects too.
While it is not too difficult to imagine that loneliness has mental health effects, it may be more surprising that loneliness has physical health effects too. Loneliness, not social network size, predicts increases in systolic blood pressure (Hawkley et al 2010). Loneliness is associated with the metabolic syndrome (Whisman 2010); a cluster of factors that have been shown to increase risk for coronary heart disease, diabetes, and stroke. Consistent with these findings, a meta-analytic study found that poor social relationships (i.e. social isolation and/or loneliness) were associated with a 32% increase in risk of stroke and a 29% increase in risk of incident coronary heart disease (Valtorta et al 2016).
However, a subsequent larger fully adjusted study found that loneliness was associated with only a 4% increase in risk of stroke and a 6% increase in the risk of heart attack – neither of which was statistically significant (Hakulinen et al 2018). However, the full adjustment in the later study included a 60-62% adjustment for depressive symptoms – which themselves may sometimes be the result of earlier loneliness (e.g. the study noted that “lonely individuals reported more depressive symptoms than non-lonely individuals”). So the true impact of loneliness and/or social isolation on stroke and heart attack may be somewhere between the findings of these two studies.
Loneliness raises the levels of the stress-sensitive hormone cortisol (Doane & Adam 2010). Feelings of loneliness the prior day were associated with an increased cortisol awakening response the following morning. Furthermore, for youth who had high chronic interpersonal stress, momentary experiences of loneliness during the day were associated with momentary increases in cortisol.
Louise Hawkley, Ronald Thisted, Christopher Masi, and John Cacioppo (2010), “Loneliness predicts increased blood pressure: 5-Year cross-lagged analyses in middle-aged and older adults”, Psychology and aging, vol. 25(1), p. 132–141. Read the abstract.
M. Whisman (2010), “Loneliness and the metabolic syndrome in a population-based sample of middle-aged and older adults”, Journal of health psychology, vol. 29(5), p. 550-554. Read the abstract.
Nicole Valtorta, Mona Kanaan, Simon Gilbody, Sara Ronzi, and Barbara Hanratty (2016), “Loneliness and social isolation as risk factors for coronary heart disease and stroke: systematic review and meta-analysis of longitudinal observational studies”, Heart, vol. 102, p. 1009–1016. Read the article.
Christian Hakulinen, Laura Pulkki-Råback, Marianna Virtanen, Markus Jokela, Mika Kivimäki, and Marko Elovainio (2018), “Social isolation and loneliness as risk factors for myocardial infarction, stroke and mortality: UK Biobank cohort study of 479 054 men and women”, Heart, 27 March, p. 1–7. Read the abstract.
L. Doane and E. Adam (2010), “Loneliness and cortisol: Momentary, day-to-day, and trait associations”, Psychoneuroendocrinology, vol. 35(3), p. 430-41 . Read the abstract.