Source: Time

By Amanda MacMillan / Real Simple

While the research isn’t entirely one-sided (there’s the weight issue, for one), several studies have suggested that married couples reap more health benefits than those who are single, divorced, or widowed. Now, a new study points to a potential reason why: Married people have lower levels of cortisol—a stress hormone that, when produced in excess, can contribute to inflammation and chronic disease.

The finding suggest that married people face less psychological stress than their single counterparts, say researchers from Carnegie Mellon University—and provide the first biological evidence to explain how committed partnerships can directly impact health.

To compare cortisol levels in married and unmarried people, researchers collected saliva samples from 572 adults, ages 21 to 55, multiple times a day on three non-consecutive days. All participants were in good health, and the researchers adjusted their analysis for personality traits—like extraversion, neuroticism, and agreeableness—that might influence their findings.

Overall, married people had lower cortisol levels than those who had never been or had previously been married. Their cortisol levels also tended to drop faster throughout the afternoon, compared to those who had never been married. (Cortisol naturally tends to be highest in the morning, but quicker declines have been linked to lower rates of heart disease and other positive health outcomes.)

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