Anne Karpf: Musical or not, you can't beat belting out a good tune

What really brings us together - and offers real health benefits - is a sing-song

I shouldn't have done it – dragged a reluctant 13-year-old to a carol service in a draughty church hall on a cold, wet Monday evening, just because her father was singing in the choir.

At first, she sat grumpily reading her novel and resolutely ignoring the massed ranks singing alongside her. But something seemed to stir when "Silent Night" started up – teenage lips were moving slowly, if my peripheral vision was to be believed. By the time we reached "O Come All Ye Faithful", there was no denying it: she was standing with me and singing lustily. Relief, she claimed later, that the ordeal was at an end, but I have my doubts. No, communal singing had got to her, as it gets to us all.

Even the most diehard non-singers find themselves mouthing the odd hymn or ditty at this time of year; Scrooge himself probably couldn't have resisted a round or two of "Santa Is Coming to Town". But singing isn't just for Christmas, and something extraordinary seems to have occurred in Britain over the past couple of decades: an all-year-round explosion of communal singing.

Last week, in Sing for Your Heart week, a profusion of sponsored sing-songs, karaoke, gigs and concerts raised money for heart research. Just under 4,000 people sang, unrehearsed, in Messiah from Scratch at the Royal Albert Hall last month – the 35th annual event organised by The Really Big Chorus. Meanwhile, the joint BBC/English National Opera's Sing Hallelujah project is encouraging people to discover the joys of singing through tackling Handel's "Hallelujah Chorus", while Sing Up, the government-funded programme to get all primary school children singing, is well under way. There are now an astonishing 2,546 choirs with websites. Forget "Bohemian Rhapsody" in the shower: today, it seems, we're all singing in public and in unison.

Those who sing in choirs agree on what they find most compelling: that it connects them to a wider group of people and a shared goal. Patrick Maynard, 48, has belonged to a choir for 10 years. "There's nothing quite like being in the middle of a sound that you're contributing to – there's a kind of physical, emotional and cognitive skill that all comes together in a performance. Often, I feel quite low after a day at work, but I always feel revived after choir. For some members, it almost functions like a singles club." One woman who'd been in an abusive marriage believes her life completely changed when she joined a choir. "People say I look like a different person and I've grown in confidence," she says.

Until I met my husband, I was frankly sceptical about all this amateur music-making. My mother was a virtuoso concert pianist, so for me music was associated with professionalism and excellence. Why do it if you couldn't excel? In my case, clearly I couldn't: my mother used to quip that I had a voice like a ballet dancer – a translation from the Polish and not, I think, a compliment.

I had my first stirrings of the pleasures of singing with others back in the 1980s at Greenham Common: collective singing made us feel as powerful as any cruise missile, something that the civil rights marchers of the 1960s had already learned. And then I discovered Frankie Armstrong.

Armstrong had been singing in public since the days of skiffle, but in 1975 she had an epiphany: in the foothills of the Sierra Nevada, at a folk festival, 70 people – most of whom declared "I've always been told I've got a terrible voice" – were, by the end of the workshop, singing in three-part harmony. Armstrong came back to Britain and started running workshops of her own – workshops where no one worried if they were singing "incorrectly".

She argues that Western Europeans, in contrast to people in more traditional societies, have been "systematically robbed of their voices" and birthright – the ballads, harvest and mining songs that were passed from generation to generation, and that spread beyond the confines of one social class. Through workshops such as Armstrong's, ordinary people recover this lost something and say that they feel more connected. What's more, according to Armstrong, once they stop worrying about it, they all seem to end up singing in tune.

Today, in addition to the more traditional choirs, you can take your pick from a multitude of "community choirs". Most are "open access", ie, you don't need to audition. They also teach by ear, so that you don't have to know how to read music. Many make a point of being reassuring, emphasising that everyone is welcome "regardless of experience". Some, such as the University of Limerick's group, give the game away in their name – Lunchtime Singing for the Terrified. The repertoire of community choirs is broad – anything from gospel and folk to world music and chanting. And most pride themselves on their democratic organisation, stressing that they are "not led" – no patronising choirmaster to point out that your F sharp is actually flat.

Why has communal singing become so popular? Recent research has confirmed what most non-professional singers had already clocked intuitively – that singing improves your health. According to Graham Welch, chair of music education at London's Institute of Education, singing is an aerobic activity that increases the amount of oxygen in the blood, and exercises the major muscle groups of the upper body. Singing can also help reduce the symptoms of colds and flu by improving airflow in the upper respiratory tract. Breathing deeply also releases tension. And a study at the University of California found higher levels of immune-system proteins in the saliva of choristers after singing a complex piece of Beethoven.

According to research by Dr Neil Todd at the University of Manchester, the sacculus, part of the vestibular system in the inner ear, is stimulated by large groups of people singing or chanting together. Since the vestibular system is also connected to the part of the brain responsible for registering pleasurable responses to food and sex, perhaps Shakespeare was on to something when he juxtaposed music, food and love, after all.

Does this mean karaoke and football chants are just as life-enhancing as a Mozart Requiem? Karaoke has had a bad press. But recent studies have found that karaoke singing brings some of the same benefits as singing in a choir and shouldn't just be a guilty pleasure. Regular karaoke performers form bonds, just like choir members, and gain confidence from singing out: they literally gain a voice. And I can personally testify that singing on the football terraces gives you a sense of belonging like no other.

In the end, it's this combination of relaxation and concentration in communal singing, along with being part of a collectivity, that is most important. We bang on about "finding oneself", but isn't "losing oneself" as important? In her recent book Dancing in the Streets: A History of Collective Joy (Granta), Barbara Ehrenreich claims that we've privileged individualism over collective endeavour, and as a result have become preoccupied with fighting depression instead of finding joy. Where, she asks, is what the French sociologist Emile Durkheim called our "collective effervescence", the ritually induced ecstasy that cements social bonds, and enables us to lose ourselves in communal festivities?

The answer surely lies in communal singing. One study found that a community choir provided homeless men with stability, comfort, social skills and a sense of hope. A women's choir in a maximum-security prison in Israel helped develop inmates' listening skills, cohesion, ability to manage their anger and self-control, and gave many their first experience of working towards a long-term goal.

The London Sing for Joy choir, started by Nina Temple when she was diagnosed with Parkinson's disease, now brings together people with chronic and degenerative illnesses. Not only do they discover physical invigoration in singing together, but they also find a freedom from the isolation of their illnesses.

Whether we know it or not, we are rhythmic creatures: even in the womb we attune to our mother's voice. Singing in unison – even if it's just joining in with Damon Albarn at Glastonbury, or singing along to Karaoke to the Sound of Music – powerfully bridges mind and body, self and other. It allows us to transcend our daily worries and reminds us that we're alive. Perhaps the moment has come for me to form a choir of people who sing like ballet dancers.

Anne Karpf is the author of The Human Voice: The Story of a Remarkable Talent, published by Bloomsbury