Hugging can lower stress, fear and anxiety, according to a new study that found a cuddle can reduce blood pressure, boost wellbeing and improve memory performance.

However, the researchers say it's only a hug from someone you know has the positive power. Embracing a stranger can have the reverse affect, Medical Daily reports.

"The positive effect only occurs ... if the people trust each other, if the associated feelings are present mutually and if the corresponding signals are sent out," neurophysiologist Jürgen Sandkühler, Head of the Centre for Brain Research at the Medical University of Vienna, said in a statement.

"If people do not know each other, or if the hug is not desired by both parties, its effects are lost."


The "cuddle hormone" called peptide oxytocin is produced in the pituitary gland and usually known for enhancing bonding, social behaviour and closeness between parents, children and couples. It's also produced during childbirth and breastfeeding to increase the mother's bond with the baby.

Researchers say the length of the hug doesn't matter, trust is the most important thing in determining if the affection will be beneficial.

Once the trust is there, boosts in oxytocin levels could be achieved simply as a result of exposure to emphatic behaviour.

"Studies have shown that children whose mothers have been given extra oxytocin have higher levels of the hormone themselves, i.e. solely as a result of the mother's behaviour," Dr Sandkühler said.

On the other hand, unwanted hugs can give us stress because our "normal distance-keeping behaviour is disregarded," Dr Sandkühler said. In these situations, people secrete the stress hormone cortisol, he said.