The study, published on March 20 in The Annals of Behavioral Medicine, 32 303 generally healthy men and women, 204 married and 99 single. Each responded to questions about martial quality, social support, and mental health. Scales were used to rate stress and life satisfaction. 

 Then each subject wore a portable blood pressure monitor for 24 hours while performing their normal activities. The groups had little difference in walking blood pressure, but married people 33 in blood pressure during sleep. People whose blood pressure does not dip during sleep are at higher risk for cardiovascular disease, according to Julianne Holt-Lunstad, 34 . 

 The unhappy married had higher daytime and 24-hour blood pressure readings than single people. Marital satisfaction is associated with satisfaction with life, lower stress, less depression, and lower walking blood pressure. 

 “Just being married per se isn’t helpful,” Dr. Holt-Lunstad said, “because you can potentially be worse off in an unhappy marriage. So, 35 .”