The Atlas of Happiness: Global secrets to feeling content and upbeat

What Russell perhaps didn't expect was how much it would capture people's imagination on this side of the North Sea, giving root to the current craze for "hygge" – which loosely translates into English as "cosy" – and even help spawn a Scottish equivalent of so-called "coorie".

"Hygge is sort of taken for granted when you are here in Denmark because it is everywhere," she explains. "There are candles on the windowsills at my kid's day-care or in the bank.

"They use hygge in every second sentence, but I don't think they were conscious that it was such a unique phenomenon or something that was only practised in Denmark because they just take it for granted. So, they have been quite baffled by the interest around the rest of the world in hygge."

This week Russell will publish her fourth book, The Atlas Of Happiness, which explores the various used by people in different countries to find contentment and wellbeing.

"Change, happiness and ways to empower women are always things that I'm thinking about," she says. "The Atlas Of Happiness was a natural next step because people kept coming up to me and talking about the happiness concepts in the countries they were from."

The former Marie Claire online editor relocated from the UK almost six years ago after her husband landed his dream job with Lego. The couple, who are based in rural Jutland, have three young children.

Russell admits she regularly draws from many of the different traditions she has written about. "Our children must be very confused – it is a cultural hotchpotch," she says. "There are a lot of candles at breakfast at the moment because it is pretty dark in the mornings.

"We try to do the Norwegian/Icelandic thing of getting outside, no matter what the weather, in full snowsuits, balaclavas – the whole shebang."

What are her thoughts on "coorie" – a subject on which there has been much debate in recent weeks? "It was interesting reading about the Scottish equivalent," she says. "Of course, many cultures do have things, but it is by labelling it that you then prioritise it. It is a good thing if more people are finding their own ways to get that feeling.

"From what I have read, people are saying it is like hygge but has got more of an outdoorsy element. Studies around happiness, wellbeing and mental health show that getting outside all year round is really good for you, so I think that can only be a positive thing."

It segues neatly to another key point Russell makes, which is her belief that optimism isn't frivolous: it is necessity. Not least when dealing with online interactions within our daily lives.

"I think with social media these days there is a sense that if you don't love something, then you must hate it, and we are encouraged towards outrage all the time. Actually, that is incredibly unhealthy and unhelpful.

"People are often levelling slurs [and accusing] others of being a bit Pollyanna-ish. Of course, there is no point sticking your head in the sand or pretending that bad things aren't happening.

"But if you only think about the bad and focus on that, then negativity bias and the way our brains work mean that we are going to cosset ourselves away. We are not going to be able to try to make things better, engage with society and the problems that we face as a community, nation or world.

"It is really important to remember the reasons to be cheerful and that there are people all round the world getting on with their lives," she adds. "Whereas, if we just live in our own bubble, watch rolling news and take on the negative parts of social media, it is almost paralysing.

"More and more people I speak to are finding it [social media] a real source of anxiety and feeling helpless. They think that they can't make a difference or do anything useful, so then they do nothing and that just seems such a shame and a waste."

For her book, Russell has researched and written about 33 different countries, from Australia to Wales, via Bhutan, Ireland, Germany, Syria, Turkey and more. The happiness concepts she imparts, however, do come with the caveat: "Nowhere is perfect. Every country has its faults."

Rather, she says, it is her intention to "unashamedly celebrate the best parts of a country's culture as well as national characteristics at their finest".

She stresses, however, that: "I'm not trying to whitewash anything. We do have to acknowledge that there is negative stuff there, but we may as well celebrate the best, otherwise what do you aim for?"

Many international cultures have their own unique traditional methods of staving off the winter blues. As the days shorten, Helen Russell shares some of her favourites:

Kalsarikannit, Finland

We've all had those evenings where we can't be bothered dressing-up or even venturing from the sofa – yet still fancy a few beers. That's where "pants drinking" comes in.

Kalsarikannit is defined as "drinking at home in your underwear with no intention of going out". From the Finnish word kalsari, meaning "underpants", and kanni, meaning "state of inebriation", Kalsarikannit is literally "pants drunk".

"That is a jolly one," says Russell. "My Finnish friends are all very laissez-faire about it and think that, of course, everyone does this sometimes. It came as a bit of a shock to them that I had never done it.

"It is light-hearted and accessible – something we can all do. There is a pleasure in that. I very much believe that you can restore yourself, so you are in a better position to go out and do good things in the world. This is an easy and quick one to get yourself in a better place."

Friluftsliv, Norway

It translates as "free air life" or "open-air living" – a philosophical term popularised by the Norwegian playwright Henrik Ibsen in his 1859 poem, On The Heights, to describe the value of spending time in remote locations for spiritual or physical well-being.

"You have got to 'earn your lunch' and 'climb a mountain,'" explains Russell. "There is a real sense, as with their Viking ancestors, that you have to do something. 'What have you done today? How have you exerted yourself?'"

Then there is what is called "utepils" – the first beer enjoyed outdoors to celebrate the weather being, if not warm, then slightly less cold. "That seems incredibly appealing after one of those long dark winters," she says. "It is something to look forward to."

Petta reddast, Iceland

Roughly translatable as "it will all work out", Petta reddast is Iceland's motto. The phrase characterises "a nation of modern-day Vikings who are easy-going with a core of grit – an unusual but powerful combination", says Russell.

The Icelandic climate lends itself to a strong interior life. In the cold and dark winter months, a rich storytelling tradition and literary culture dating back centuries comes to the fore. Another thing that helps Iceland rank highly on happiness lists, she says, is the fact they are big readers.

"There is this idea that if you really cannot get outside, there is a lot than you can use your imagination for and really delve into books. There are lots of studies showing that reading is good for us and it helps to develop our empathy to share stories."

Azart, Russia

This is the Russian concept of what Russell describes as "seeking heat". As she explains: "With Chekhov and Turgenev, all these old Russian writers, it is never a happy-go-lucky type of happiness.

"It is a passion and a drama – that is part of the pleasure of it. Russians are good at skipping the small talk.

"Things like the Russian banya – the saunas – where you are beating yourself with birch twigs and then rolling in the snow. There is this idea that if the weather is quite cold anyway, it is almost punishing yourself a little further so that your base line, the reality, doesn't seem as bad."

Joie de vivre, Canada

Or "joy of living" as it is known in English. "Canadians are really good at getting out in all seasons and opening up their social circle, socialising and celebrating diversity, which is hugely helpful to remember in these divided times," says Russell.

It is something that she – as part of an international community in Denmark – can relate to. "The more different nationalities that you end up interacting with and opening up your social circle to, it means there are so many more reasons to celebrate throughout the year.

"Regular rituals, spending time together and having things to look forward to have been proven to be good for us."

Lagom and Smultronstalle, Sweden

Pronounced "lah-gom", the first comes from the Swedish word lag or "team". It is often described as an equivalent to the Danish concept of hygge, but there are stark differences.

"We have all heard about lagom but one of the things that doesn't get talked about outside of Sweden so much is the sharing aspect of it," says Russell.

"There is this thing in lagom where with the last slice of cake you cut it in half and then you cut it in half again. Everybody keeps cutting it in half until it is the tiniest crumb because you would never take the last piece from your fellow countryman or woman.

"You are always mindful of them, thinking about them and sharing. So, although in Sweden – as with many of the Nordic countries – there is an increasing anti-immigration feeling, and this idea of them as a utopia is slightly naive, they are pretty good at sharing.

"The Swedes can be quite insular," adds Russell. "When they need to restore their energy, they have what is called 'smultronstalle' – based on a symbolic wild strawberry patch from old children's books. It can be anywhere you feel at one with nature.

"You go there by yourself to restore. Afterwards, you are in a better place mentally and ready to face the world. I have spoken to people who said it is a special glade, a favourite chair, a nearby hill – or even the back of their walk-in wardrobe among the coats like Narnia.

"So, that is something helpful and doable. Everybody can find a little space that is just for them, to take some deep breaths and think. I am a lot more patient with my children once I have done that."

The Atlas of Happiness by Helen Russell is published by Two Roads on Thursday (November 1), priced £16.99