I jump over a small creek, climb up a steep, shaded slope and suddenly find myself surrounded by sky-high bamboo. Leaning in over the trail from both sides, the thick bamboo limits the passageway to a low and narrow tunnel of vegetation.

I follow Sheena from England, who is in front and gracefully bows her whole body, making her way through. Like her, I tighten my abdomen and bend at the hips, trying to keep my spine straight. It’s a movement we were taught during a mobility course earlier in the day, designed to shift the weight to our hips and glutes, to make the hike easier on our feet.

We’re on an excursion with Nefeli Nine. The name “Nefeli” derives from the ancient Greek word nefos meaning “cloud”, so… Cloud Nine Retreats. Just an hour’s drive northeast from Athens, they’re based in a luxurious stone villa with sea views from every room. The weeklong retreat is made up of three types of training: yoga, fitness and hiking. We work out, rest and laugh – a lot.

Before breakfast every morning, we spend 45 minutes moving and stretching all the joints of the body. As we stretch together, founders Stephanie Contomichalos and Emilio Devoti explain which muscles are at work during every bend and twist. It’s called pre-hab, Emilio tells us, and just like each component of the retreat, is designed to complement the other activities.

Each daily hike is different: some days we walk along the coast, while on others we drive up into the mountains, where we discover waterfalls, the old quarries of Mount Penteli (where the marble for the Acropolis was extracted), and panoramic views of the valleys, lakes and dams – all set against a backdrop of the sea on the horizon.

Nature here is bountiful, despite the evidence of human intervention. The air is alive with the scent of herbs and damp earth. Our legs brush against rockrose, juniper shrubs, and fern-like wild asparagus. On one hike, our guide Archelaos holds up a juicy variety of mushroom. Yellow with a white core, it is a Lactarios deliciosus, he tells us, and just as scrumptious as the name suggests. We pick three handfuls.

Back at the stone villa, the mushrooms are sautéed with garlic and parsley. As they’re placed steaming on a plate, on a long dining table, we raise glasses of Greek red wine. After all, we deserve to indulge; our four-hour hike was followed by a 90-minute workout by the pool. And, of course, we need to gather our strength for tomorrow.

“You can lead a retreat where people come for the experience, but forget everything the moment they leave,” Stephanie says. “Or you can teach skills and techniques that they can easily adapt into their everyday lives.”

Stephanie and Emilio encourage a healthy lifestyle that’s also enjoyable. Their approach is inspired by author Dan Buettner’s “The Blue Zones Solution,” which shares useful lessons from centenarians around the world. They cook delicious, mostly plant-based meals containing “longevity foods” from the island of Ikaria, such as olive oil, honey, herbal teas and chickpeas (in the form of Stephanie’s delicious hummus).

According to Buettner, if you want to live to a hundred, joining a gym won’t cut it. You need to embrace many small lifestyle changes; like moving naturally through walking or gardening, for example, or sipping a little wine in the afternoon.

“I believe in Greece,” says Emilio. “I think there’s still time and space to create a healthy and sustainable life here.” But in a high-paced and tumultuous city like Athens, surrounded by crowds, traffic and so many things to see and do, it’s hard to slow down.

Of course, health retreats are available across Greece, but there’s something magical about joining one so close to Athens – simply because it offers such a marked contrast. Just an hour away from the hustle and bustle, as we practice our yoga breathing exercises, I look out at the clouds and their shadows on the sea. I feel my mind declutter. This is how Greece should be.