Loneliness and Blood Pressure in Older Adults: Defining Connections

Abstract

Social isolation impairs physiological functioning and shortens lifespan in members of various social species, from fruit flies to mice, rats, rabbits, pigs and chimpanzees. In humans, the mere perception of isolation is sufficient to incur adverse outcomes [1]. We call this perception loneliness. Loneliness confers a unique risk for a wide range of physiological and health outcomes. Prior research has shown that loneliness increases hypothalamic pituitary adrenocortical activity, diminishes immunity and alters gene transcription control pathways in ways that favor heightened inflammation. Loneliness has also been shown to prospectively predict a worse profile of cardiovascular risk (e.g., overweight, high systolic blood pressure [SBP], elevated total cholesterol, low levels of high-density lipids, elevated glycated hemoglobin), poor sleep quality and daytime fatigue, diminished likelihood of physical activity, progression of Alzheimer’s disease, and increased risk for mortality [1–3]. Loneliness is related to, but distinguishable from, social isolation and separation. People differ in their need for affiliation (e.g., intro version/extraversion) and in their perceptions of social circumstances, such that low levels of social involvement are perfectly acceptable if not preferable for some individuals, whereas even high levels of social involvement are insufficient to stave off feelings of loneliness among those who perceive their social relationships as defi cient in quality. The distinction between social isolation and loneliness clarifies why aging does not inevitably confer loneliness. Not until oldest old age does the prevalence and intensity of loneliness increase to the high levels seen in young adulthood [4]. Developmentally, it appears that loneliness peaks when one’s sense of connectedness is being forged independently of parents and then again when one’s sense of connectedness is being threatened by the gradual and inevitable loss of a lifetime’s worth of social relationships. At both junctures,