From easing pain to boosting sleep, what falling in love does to your body and brain

THE process of falling in love may be universal but, until recently, our understanding of the mechanisms that contribute to romantic love — and its effects on us — was limited. Now a growing field of ‘ love science’ is teasing out the impact that this powerful emotion can have, psychologically and physiologically.

One of the most recent studies, published last month in the journal Behavioural Sciences, found that the brain reacts differently when a person is in love, essentially making the loved one the centre of their attention.

Researchers at the university of Canberra and university of South Australia surveyed 1,556 young adults who identified as being ‘in love’ about their emotional reaction to a partner, their behaviour around them and the focus they placed on them.

They concluded that in romantic love, a mechanism known as the behavioural activation system ( BAS) is triggered, which makes a person prioritise their beloved above everything else.

As the lead researcher, anthropologist Adam Bode, explained, this link to the BAS ‘shows that even though love is about strong emotions, ultimately the evolutionary goal is behaviour — to make us pursue our mates, care for them and have lots of sex’.

This change in behaviour is governed by brain chemical alterations, adds researcher

Dr Phil Kavanagh: ‘We know the role that oxytocin [the ‘ love hormone’] plays in romantic love, as we get waves of it circulating throughout our nervous system and bloodstream when we interact with loved ones.

‘The way that loved ones take on special importance, however, is due to oxytocin combining with dopamine [the ‘feel-good hormone’], which our brain releases during romantic love.’

This, in turn, activates brain pathways associated with positive feelings, which makes us continue that behaviour.

BUT it’s not just the BAS system that is activated: love sets off a massive physiological reaction throughout our body. While you might think that sharing a bed would lead to more disturbed sleep, sleeping with your partner actually seems to increase rapid eye movement (REM) sleep — important for regulating emotions, memories and creative problem-solving.

In a 2020 study by Christian-Albrechts university of Kiel in Germany, the brains of young couples were scanned over four nights, when sleeping together and apart. This showed that although sharing a bed did lead to more disturbance due to limb movement, it also led to betterquality sleep.

‘While your body is a bit unrulier when sleeping with your partner, your brain is not, and it might give you an extra boost when it comes to your mental health, memory and problem- solving,’ said lead researcher Henning Johannes Drews.

Another recent discovery is the impact love has on our gut microbiome. This diverse community of gut bugs has an effect on everything from digestion to brain function.

Research in 2019 by the university of British Columbia showed that people in close relationships, with sustained physical contact, have the most diverse gut microbes of all. Published in Scientific Reports, this builds on earlier studies that showed a mere kiss can transfer around 80 million bacteria between couples.

One of the best- documented effects of being in love is how it can reduce chronic inflammation — and, as a result, the risk of serious illnesses such as diabetes, heart disease and some cancers.

A study last year by the university of North Carolina found that spending time with a partner reduces the level of C-reactive protein (CRP), a key indicator of chronic inflammation.

The scientists tested CRP levels in 100 people in relationships over a month, and they completed questionnaires about spending time with their lovers.

Writing in the journal Brain, Behaviour, and Immunity, the researchers reported that the more time participants spent with their partner, the lower their CRP levels were the next day.

Meanwhile, a 2019 study found that being in a loved one’s presence can also reduce pain, even if you don’t touch or talk.

Researchers at the university of Health Sciences in Austria recruited 48 couples and tested their resilience to pain when they were alone, and again when their loved one was in the room. They found that both men and women appeared to be more resilient when they were with their romantic partner.

‘ Repeatedly, talking and touching have been shown to reduce pain, but our research shows that even the passive presence of a romantic partner can reduce it,’ said study author, Stefan Duschek, a professor of health psychology.

underpinning many of the physiological effects of love is the release of oxytocin (which is also responsible for the euphoria we feel when falling in love).

Oxytocin is well known for relaxing us, helping us bond with our partner and reducing stress.

And it may help with stressrelated gut disorders. A study by Penn State College of Medicine in the u.S., published in the Journal of Physiology, showed that oxytocin can reduce digestive symptoms linked to stress — including constipation, bloating and nausea — as it increases muscle contractions in the stomach.

Separately, researchers have discovered that the love hormone (stimulated by touching and cuddling) encourages hair growth. The 2023 study, published in Scientific Reports, builds on existing research that shows oxytocin promotes the growth of dermal papilla cells which play a vital role in hair growth.

Love also promotes a surge in dopamine, which influences many bodily functions such as memory, movement and mood. In January, a study by neuroscientists in the u.S. showed dopamine levels surge when we anticipate being with our lover.

If we are due to meet a partner for dinner, for example, dopamine will spike in the hours beforehand, motivating us to make the journey. (If we’re only meeting, say, a work acquaintance, that dopamine surge doesn’t happen so we may choose to stay at home.)

The dopamine surge for love is beneficial for our health, the neuroscientists said, as it drives us to maintain those bonds. It may also explain why it’s so difficult to get over some relationships.

After a split, this reaction usually dies down, so even if you meet again there’s less of a surge. The theory is it’s nature’s way of allowing us to move on. But some people don’t move on as quickly as others, and the study authors think this may be due to a faulty dopamine response.

‘It’s possible that, for these people, their partner-associated dopamine signal isn’t adapting after loss, essentially stalling their processing of the loss or breakup,’ says lead researcher Zoe Donaldson. ‘A larger goal is to identify those biological changes that help people re-engage with life — which may lead to tailored therapies or even medication.’

MEANWHILE, unrequited love can cause addiction-type behaviour, says Dr Emilia Vuorisalmi, a medical doctor in Finland: ‘Every cell of our body wants to be with the loved one. If, for some reason, it doesn’t happen, our dopamine levels drop, and stress hormones cortisol and norepinephrine are released in order to get them back.

‘This is evolution’s way to ensure our genes move to the next generation. If we don’t succeed in our goal, we can try to feel better by self-medicating. Maybe we start training for a marathon or turn to an inappropriate relationship, alcohol or drugs to soothe the pain, as these behaviours may temporarily increase dopamine levels,’ she says.

Hana Burianova, a neuroscientist and psychologist at Swansea university, adds: ‘unrequited love can increase cortisol and adrenaline, which can cause problems associated with stress, like inflammation, anxiety and insomnia.

‘uncertainty also causes stress. So using online dating platforms and having different dates all the time can invoke similarly stressful responses and be detrimental to your health — especially if associated with disappointment. Taking breaks from these kinds of stressors would be a good idea.’