The early evening air of Madrid’s much-traversed Plaza de Antón Martín is gripped by a familiar theme. Toddlers tug lovingly on parents’ paws. Senior citizens wedge their mitts into the warm fold of their spouses’ arms. A non-stop parade of pedestrians plays out in pairs, five-abreast families or even bigger clusters of friends. A flock of six babbling abuelas (grandmas) – all joined at the palms – pause to admire the 21 torsos encompassing the square’s monument The Embrace, standing as a rusted-on reminder of how the city’s affectionate support system has seen it through tougher times. Hold on to this picture of interlocking hands because it’s key to understand this touchy-feely crowd’s oldest secret.

Madrileños are old. Some of the oldest, in fact. The OECD says that the lifespans in the Spanish capital are the highest in Europe. At an average of 85.2 years, Madrileños outlive even Japan’s impressive 84.1-year stalwarts. A closer read of the stats, though, suggests that the underlying causes of longevity aren’t exactly a settled science. Acknowledging the way that the capital encapsulated Spain’s regional diversity, poet Antonio Machado once surmised Madrid as “the breakwater of all Spains”. Uttered almost a century ago the verse still rings true; this city remains a microcosm of national trends and traits.

Data shows that today’s Spaniards work more, exercise less and even breathe unhealthier air than their European peers (although sweeping new policies to limit inner-city traffic in Madrid are making up for lost decades of dithering). On the upside, Madrid soaks up one of the highest doses of sunlight of any European capital and while bad habits have drifted downward in recent years, the facility for fun under the sun could explain still-dizzying levels of alcohol and tobacco consumption.

Maybe the curative qualities of the Mediterranean diet balance out the effects of insalubrious vice? Just look at the city’s thriving food scene, where a farrago of fresh produce, nuts and fish is peppered across dinner plates. And even though the city is landlocked, a steady supply of omega-3 pours out of Mercamadrid, the world’s second- biggest seafood market (outdone only by Japan), while a revival inside fraternal municipal food markets means they remain a cornerstone of barrio life. But peddling quality produce is only half of the healthy equation.

“I’ve grown special connections with my butchers, fishmongers and fruit sellers,” says Fernanda Ruíz, who MONOCLE finds foraging among the bustling stalls under the soaring roof of Mercado de la Paz at 10.30 on a Friday. The septuagenarian swears by her daily shopping routine, talking up the benefits of cheerful chatty face time. “These are genuine relationships; my shopkeepers often show an interest in my wellbeing.” Thanks to Spain’s strong farming sector, the vitamin-rich content of her basket is affordable too.“In Spain the way we relate to each other is bound by a connection to food,” says Pilar Zueras, a research fellow from the CED, one of the country’s leading centres for demographic studies. “The simple human need for nutrition has evolved into a shared social act, uniting family, friends and co-workers – much more than in many other countries. Social support is associated with survival,” she says, detailing how connections are measured in terms of quality rather than quantity.

“Generally, Spanish people are more open to creating social bonds; we’re more touchy-feely,” she says, adding that questions about welfare never come across as prying or imprudent. “In Spain, when we ask, ‘How are you?’ we mean it.” The feeling of belonging in one’s community also helps. “From volunteering to attending Sunday church services, going to your local bar or playing weekly card games, an active, inclusive lifestyle not only contributes to longer life but also the number of years in good health,” says Zueras.

Right across Madrid, an insatiable appetite for social connections puts fire in the collective belly. It spikes around midday. You only need to stand in the door of any restaurant before 14.30 to witness the religiously punctual wave of ravenous patrons; they prove that lunch is the city’s most treasured (and perhaps healthiest) tradition. The menú del dia, or set menu, may be a relic of the Franco era (enshrined in law to ensure itinerant workers could enjoy a fulsome meal) but it remains a venerated institution, meaning a €10 three-course meal is still surprisingly easy to come by.

Over in Madrid’s upper-middle-class district of Chamberí, the clock has just struck three and automobile executive Gerardo Martínez Sánchez is listening to his chirpy daughters Candela, eight, and Isabel, six, relay today’s edition of schoolyard news around the family kitchen table. “With our busy jobs, we’re running around all day – but lunch gives us a chance to stop,” says Gerardo. Pouring herself a glass of red wine, his wife Elena Rodríguez Álvarez, a language teacher, tucks into a table laden with jamón, a tuna-and-egg salad and a plate of sheep’s milk cheese. “We have the option to let the kids eat lunch in their primary school cafeteria but making the extra effort gives us valuable time to reconnect as a family,” says Elena. “Many of our friends do the same.” When it comes to cultivating closeness, Madrid’s urban layout has a lot to answer for. In some suburbs, the city centre packs 45,000 people into each square kilometre, making it one of Europe’s most high-density cities. It’s full of independent commerce of every stripe so Madrileños rarely have to stray from sus cuatro manzanas (a colloquialism meaning “four local street blocks”) to buy food, pull up a bar stool for a cheeky afternoon beer or submit household items for repair. This helps ageing citizens – many of whom can still be spotted hobbling to the beat of their time-worn routines – maintain their favoured daily structure. Compact street life makes the prevailing sense of togetherness almost the default.

Sitting inside the plywood, polyhexagonal-contoured hut he co-designed for the pavement in front of city hall, Alberto Nanclares, architect and member of cultural collective Basurama, is waxing lyrical about Madrid’s stoic social mores. “I’m not sure how many people have struck up conversations here – or if anyone has fallen in love – but we envisaged it as an antidote to anonymity.”

The introspective installation is part of the municipal exhibition La No Comunidad (The Non-Community), which ponders the paradoxical sense of isolation in modern cities. Mirroring the radar-repelling hulls of stealth aircraft, the structure’s geometric surface is a remark on how the overuse of technology risks turning city dwellers into undetectable denizens. A sign at the entrance to the space indicates that this is a rare mobile phone-free zone.

As we sit on the wooden seats inside, several curious passers-by drift in and offer casual opinions before continuing on. “The space has taken on a life of its own,” says Nanclares. “Perhaps the parochialism of Spain’s Catholic roots provides a natural bulwark against loneliness. Madrid’s non-aggressive character certainly helps too.” Under the watch of 74-year-old mayor Manuela Carmena, who has cultivated genuine political appeal with her grandmotherly touch (even sharing cup-cake recipes with constituents), a commitment to community life has informed a sweeping, strategic plan, Madrid: City of Care. The spirited initiative suggests that, even in a community-spirited city like Madrid, efforts are being made to ensure no one is left behind.

“Cities have long centred their priorities around productivity; this government takes a different approach guided by the belief that emotional needs are just as important as economic ones,” says Mónica Díaz López who co-ordinates the pilot programme Confidants against Loneliness. Rather than resort to paternalism, the trial effort to combat solitude opted for recruiting pillars of the community – people such as bakers, news agents and pharmacists – to reach out to at-risk individuals and invite them to partake in inclusive activities.

Recently the leafy sub-district of Trafalgar organised a community stroll, which saw dozens of strangers rediscover their neighbourhood through a tour that was themed around good eating. Participants were introduced to healthy food shops and restaurants, with social encounters sprinkled along the way. “It’s about empowering people to self-organise,” says López, who charts progress with surveys that quiz residents on their sense of neighbourhood pride and asks more personal questions about whether people feel loved.

“The way cities are built can either facilitate or hamper social relations,” says López, arguing that Madrid’s vibrant network of plazas need to prioritise public seating, vegetation and shade before the commercial creep of restaurant terraces. The chance of isolation is also being countered through the reimagination of urban fixtures. On central boulevard Gran Vía, MONOCLE bumps into effusive senior citizen Francisca who, unprompted, declares that she is one year shy of 90. She’s perched on one of several newly installed public benches, which were designed to accommodate multiple strangers. Sporting some fancy new pink footwear, she poses proudly while son Jesús snaps portrait shots with his phone. “My secret to a long life is to live it,” she says, before a farewell that involves several tight hugs.

Madrid’s rituals – many of them rollicking fun – embellish the unseen edifice of the everyday. The importance of the paseo, or evening stroll, is not to be underestimated. As the daylight simmers down, street activity dials up, populated by zigzagging walkers who ensure the hours between 18.00 and 20.00 are the zenith of quotidian life. It provides an opportunity to debrief on the day’s happenings, bump into friends or simply savour the collective positive energy that bounces off the pavements at this particular hour.

And annual traditions mean that there are always (somewhat cathartic) communal associations to look forward to. In July the city’s liberal (and often libertine) reputation is on colourful display during the Gay Pride parade, which draws millions of Madrileños (of all persuasions) onto the streets for the unofficial ushering in of the summer. New Year’s Eve is celebrated with the collective consumption of 12 grapes, downed ceremoniously with each chime of the midnight clock (and an accompanying wish). Even Spain’s mammoth December lottery, El Gordo, which captivates the country several days before Christmas, is structured in a way that sees winning numbers divided into fractions of 10, making it a joint wager between willing family and friends. Meanwhile the evening aperitivos – celebrated most days – provide a regular opportunity to call up a friend, say cheers and chinwag over cañas or vermouth.

Walk any day in a Madrileño’s shoes and you’ll quickly realise that the joie de vivre that is infused into shared meals, evening strolls and frenzied fiestas speaks to Madrid’s steely resolve to remain young at heart. It’s 19.30 and along the popular riverbank paths of the Madrid Río park, tonight’s array of all-aged finger-locked foot traffic seems untroubled by any thoughts of life expectancy. Rather than a numbers game, life is embraced in similar form to their leisurely paseo: a light-spirited pace, which goes hand in hand with a more fulfilled – and shared – journey. It may come naturally to them but these meandering masses seem to hold the meaning of life (or, at least, the secret that garners life with meaning) firmly within their grasp.