Partner's scent eases women’s response to stress

(Reuters Health) - During a stressful time, smelling a partner’s scent might help ease anxiety, a study suggests.

Stress levels dropped in women who smelled their partner’s shirt during a stress test but rose in women who smelled a stranger’s shirt, researchers found.

“Many people wear their partner’s shirt or sleep on their partner’s side of the bed when their partner is away but may not realize why they engage in these behaviors,” said lead study author Marlise Hofer, a psychology graduate student at the University of British Columbia in Vancouver, Canada.

“A partner’s scent alone, even without their physical presence, can be a powerful tool to help reduce stress,” Hofer told Reuters Health by email.

Hofer and colleagues worked with 96 couples, most in their early 20s, to complete the study. They asked the men to wear a white T-shirt for 24 hours without deodorant or scented products. Then the shirts were turned inside out, folded and placed in a sealed plastic freezer bag with the underarm section facing the opening.

The women participated in the Trier Social Stress Test, which includes a mock job interview and unanticipated mental math question that causes a stress response. They were randomly assigned to smell a single shirt three times before and three times after the stress test. The shirt might have been worn by their romantic partner or a stranger, or it might have been new and unworn.

The women also completed a questionnaire five times during the experiment to indicate anxiety, physical discomfort, tension, desire to leave the situation and feelings of control. Saliva samples were collected seven times during the experiment to measure levels of the stress hormone cortisol.

The research team found that perceived stress changed during the experiment for most women, and those who smelled a partner’s shirt felt less stressed both during and after the stress test than those who smelled a stranger’s or unworn shirt.

The researchers were surprised to find that cortisol levels were higher after the stress test in women who smelled a stranger’s shirt. “These unanticipated findings could serve as a source of future research,” Hofer said.

Cortisol levels didn’t differ between women who smelled their partner’s shirt and an unworn shirt.

Dr. Donald McBurney, professor emeritus of the University of Pittsburgh in Pennsylvania, has researched olfactory comfort in close relationships. “In our studies, we received many anecdotes, including lovers who mailed worn clothing back and forth between military members and their partners back home,” McBurney, who wasn’t involved in the new study, told Reuters Health by email. “And hospitals give infants items of their mother’s clothing to sleep with.”

Future research should investigate whether perceived stress and cortisol responses are the same for men and if additional factors could reduce stress for both men and women, said Dr. Sean Mackey of the Stanford University School of Medicine in Palo Alto, California. Mackey, who wasn’t involved with this study, has researched romantic relationships and experiences of pain.

“Can we further manipulate this (decreased stress) response and amplify it?” he wrote in an email to Reuters Health. “How does the strength of the (romantic) relationship affect the response?”

Beyond a controlled laboratory setting, researchers should also study how this works in real-world applications, he added.

“During times of stress, keep those you love close to you,” Mackey said. ‘If you are going to be away during a stressful period, it may be useful to bring an article of their clothing.”