Having trouble sleeping? Forget counting sheep. All you may need is your romantic partner's favourite T-shirt wrapped around your pillow, as researchers have found that the scent of a romantic partner can improve sleep.
The study, published in the journal Psychological Science suggests that the scent of a romantic partner can improve your quality of sleep. This is true regardless of whether or not you are consciously aware that the scent is even present.
"A growing body of evidence has shown that close relationships are essential to our health and well being," said study co-author Frances Chen from the University of British Columbia in Canada.
"But far less is known about the role of scent in relationships and social support processes. The current study provides new evidence that the mere scent of a romantic partner improves sleep efficiency," Chen added.
Previous research has shown that romantic relationships and close physical contact can provide many physical and mental benefits, including aiding in a good night's sleep.
Other research has shown that scents can have profound and evocative effects on the brain. What has not yet been clearly demonstrated is a direct connection between the two.
For the findings, the researchers set out to investigate this intersection and to understand how romance, scent, and sleep interact.
They began their research by asking one member of a heterosexual couple in a long-term (three or more months) relationship to wear a plain cotton T-shirt for 24 hours.
During this time, the wearer was to avoid typical scent-producing behaviours, like eating spicy food or doing vigorous exercise. They were also told to avoid perfume, cologne, and antiperspirants.
The T-shirt was then hermetically sealed and frozen.
Afterward, the second member of the couple was given two identical shirts, one previously worn by their partner and another that either had been previously worn by a stranger or was scent free.
When a participant used their partner's worn, scent-bearing T-shirt as a pillowcase, they experienced an average of over nine additional minutes of sleep per night.
This equates to more than one hour of additional sleep per week, achieved without spending any more time in bed.
The increase was due to participants sleeping more efficiently, meaning they spent less time tossing and turning.
Sleep efficiency was measured using a wrist-worn sleep monitor that tracked movement throughout the night, the study said.
Participants also gave self-reported measures of sleep quality each morning, which increased on nights they thought they were sleeping with their partner's scent.
"The effect we observed in our study was similar in magnitude to that reported for melatonin supplements--a commonly used sleep aid. The findings suggest that the scent of our loved ones can affect our health in powerful ways," said study researcher Marlise Hofer.
This research suggests that simple strategies such as taking a partner's scarf or shirt along when travelling may have measurable effects on our sleep.