In their study, Dr. Grewen and colleagues measured plasma oxytocin, norepinephrine, cortisol, and blood pressure responses in 38 heterosexual couples aged 20-49 years who had been living together for at least 1 year. Each couple spent 10 minutes resting separately and then 10 minutes seated together talking about close time spent together and watching a "romantic" video (called the "warm contact period"), followed by a 20-second hug, after which they were separated for a 10-minute rest period alone.
Higher partner support, assessed by self-report, was related to lower SBP at the end of warm contact in both men and women, although the effect was greater in women. Both men and women who reported high partner support had higher levels of plasma oxytocin, but levels were linked to lower blood pressure at baseline and to lower levels of norepinephrine throughout the study only in women. Dr. Grewen and colleagues believe that the potentially cardioprotective effects of oxytocin on sympathetic activity and blood pressure may be greater for women.