A romantic partner’s scent, particularly one that is attached to clothes, could reduce the levels of stress hormones, a study suggests.

“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 behaviours,” lead author Marlise Hofer, of the University of British Columbia, said.

In the study, a woman who picked up her partner’s smell had lower levels of stress, but the opposite happened when she smelled another person’s shirt.

Researchers included 96 opposite-sex couples in the study. Males were given a T-shirt to wear for a whole day and advised to avoid eating anything that could alter their smell, wear deodorants, smoke, use scented-products. The T-shirts were then frozen to keep the smell.

Females were designated to “smell” as the researchers noted they have better sense of smell. The participants blindly smelled the shirts - which were either unworn, worn by their partner or that of another, and then underwent a mock job interview and mental math task.

The women also answered questions about their stress levels and gave saliva samples.

“Those who both smelled their partner’s shirt and also correctly identified the scent also had lower levels of cortisol, suggesting that the stress-reducing benefits of a partner’s scent are strongest when women know what they’re smelling,” the researchers said through their release.

On the other hand, women who smelled a stranger’s shirt were likely to have higher cortisol level.

The researchers explained that the finding could be related to evolutionary factors such as fear of strangers.

The unfamiliar male scent must have triggered the ‘fight or flight’ response, causing the elevated stress hormones.

“This could happen without us being fully aware of it,” Prof. Hofer said.

The researchers suggest that countering stress could be as simple as bringing a clothing article owned by a partner.

“Our findings suggest that a partner’s scent alone, even without their physical presence, can be a powerful tool to help reduce stress,” she concluded. MIMS