FRIDAY, May 24, 2002 (HealthDayNews) -- Lonely heart. Broken heart.
These terms are not medical ones, but they may have their roots in biological truth because new research shows lonely people have a greater risk of heart disease.
The reason for it could be the way their cardiovascular system functions, says a new study in the May/June issue of Psychosomatic Medicine.
Researchers gave 99 male and female Ohio State University undergraduates a questionnaire to determine whether they were lonely. The researchers then monitored their blood pressure, heart rate and cardiac output while they did stressful tasks. The tasks included math problems, and writing and giving a speech to defend themselves against a false accusation of stealing.
Blood pressure rose for both the lonely and non-lonely students during both tests. The reason for it was increased cardiac output, or the amount of blood the heart is pumping, considered a healthy response to dealing with stressful situations.
However, what happened to the lonely students blood pressure before and after the tests may yield clues about the reasons for heart disease in people who are socially isolated or perceive themselves to be socially isolated.
The lonely students had chronically higher levels of what's known as vascular resistance and lower levels of cardiac output during rest -- that is, before and after the tests.
Vascular resistance occurs when the arterioles (small arteries) are too constricted to handle the increased output from the heart, making it more difficult for blood to flow, hence, raising pressure.
Over time, both vascular resistance and chronically high blood pressure are risk factors for heart disease.
In the long run, vascular resistance could increase wear and tear on blood vessels, increase the likelihood of blockages and could increase blood pressure, says study co-author Louise Hawkley, a research scientist at the Institute for Mind and Biology at the University of Chicago.
"If these cardiovascular systems continue to operate this way in the long run, you could set yourself up for hypertension (high blood pressure) and heart disease," Hawkley says.
To get at the longer-term implications of loneliness, the researchers did a second test using 25 men and women aged 53 to 78 who were generally healthy for their age. This group was also given the loneliness questionnaire.
The researchers found blood pressure was linked to age in the lonely group. The people in the oldest half of the lonely group had blood pressure that was significantly higher than the people in the younger half of the lonely group.
This finding is consistent with the idea that, over time, vascular resistance in the lonely can lead to hypertension, Hawkley says.
In the non-lonely group, blood pressure did not show the same correlation to age and was, in fact, stable across the ages.
The study also found few differences in behaviors that could affect blood pressure among the lonely and non-lonely, including drinking alcohol, smoking, diet, exercise and compliance with medical treatments.
However, the researchers did find the lonely had more sleep problems.
Sarah Knox, a psychophysiologist at the National Heart Lung and Blood Institute, says the findings are "very interesting."
"There is a large body of research that shows people who are lonely die sooner," Knox says. "We know they have poorer cardiovascular health. This study is getting at some of the reasons for that."
What To Do: For tips on overcoming loneliness, read these articles from University of Iowa HealthCare or campusblues.com.
