PHILADELPHIA (CBS)—A new study suggests that married people are healthier than those who are single.

The study was conducted at Carnegie Mellon University and published in Psychoneuroendocrinology.

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To conduct the study, researchers collected saliva samples from 572 healthy adults aged 21-55 over three non-consecutive days. Multiple samples were taken during each 24-hour period and tested for cortisol.

Researchers found that married individuals had lower levels of the stress hormone cortisol than those who never married or were previously married.

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The findings support the belief that single people, including those who are divorced or windowed, face more psychological stress than married individuals.

“It’s is exciting to discover a physiological pathway that may explain how relationships influence health and disease,” said Brian Chin, a Ph.D. student in the Dietrich College of Humanities and Social Sciences’ Department of Psychology.

Researchers also compared each person’s daily cortisol rhythm. Those who were married showed a faster decline, a pattern that has been associated with less heart disease, and longer survival among cancer patients.

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“These data provide important insight into the way in which our intimate social relationships can get under the skin to influence our health,” said laboratory director and co-author Sheldon Cohen, the Robert E. Doherty University Professor of Psychology.