The fixed safety lines and ladders of the via ferrata wind their way up to the 2,400m summit of Col dei Bos. I step into the climbing harness, contemplate the 500m of near-vertical limestone rock and feel my courage falter. As lighthearted conversation turns to a more matter-of-fact briefing, Diego Zanesco – half mountain goat, half silver fox and 100 per cent cool customer – settles my nerves. He’s one of the most respected guides here in the Alta Badia region of the South Tyrol, with more than 30 years of experience under his belt, and you can feel it. I clip the carabiner on, grip the cable and get down to business.

It is day one of four in the Dolomites, where I am a guest at Rosa Alpina Hotel & Spa in San Cassiano – a legendary property, equal parts luxury chalet and rustic mountain lodge, with a multi-Michelin-starred destination restaurant, St Hubertus. It joined the Aman stable of hotels and resorts last year, but the Pizzinini family, its founding owners, remain a constant presence here: Hugo Pizzinini, the third-generation scion, was on hand to personally welcome me with a spaghetti carbonara when I rolled in from Venice at 10.30pm.

The author running over Forcella Salares, with a view down the valley and the Scotoni mountain hut

I am staying to test-run Aman’s new programme of multi-day extreme sports retreats, aimed at guests with a thirst for ultra-physical adventures layered with all the luxuries you’d expect from these hotels: massages, expert guides, fine cuisine and finer spas. Each retreat is tailored to leverage its respective landscape to the fullest: a desert-mountain adventure in Morocco, a triathlon through the rainforest of Phuket, ocean challenges on a private island in the Philippines, and, here in the Dolomites, serious alpine adventures. Though the daily activity plans are fairly hardcore, everything is fairly minutely customisable to suit ability, length of stay, weather conditions and how you’re feeling on the day.

My predilection for endurance sports perfectly matches the terrain and its mountain traditions, so running, cycling and swimming are the mainstays of my itinerary. They vary in intensity and duration: some truly limit-pushing, others much more pleasurable, with doses of via ferrata thrown in for alpine adrenaline.

The trail run up to Sass de Stria

The Alta Badia region is a particular hotspot for road cycling, with several stunning mountain passes. The Giro d’Italia is a regular visitor, and the Maratona dles Dolomites starts and finishes a stone’s throw from Rosa Alpina. With an international field of 9,000 entrants taking part, it strings together several passes into one epic ride, covering 138km and gaining 4,230m in elevation. (To put that into context, a ride of that distance in England would typically have around one third as much climbing.) It’s the kind of challenge that I’m seeking. The Rosa Alpina equips me with a Pinarello – a top-spec, ultra-lightweight Italian carbon road bike (in Ferrari red, naturally) and issues me with a guide, Franz Wieser – a tall, reedy 26-year-old who looks every bit the champion cyclist. Regardless of the activity, it seems, the hotel is ready with expert athletes to both instruct and push the guests.

The initial two-way buzz of conversation soon becomes a Franz monologue – I barely manage monosyllabic replies between gulping breaths as I realise my morning rides around Richmond Park have been laughably insufficient compared to the challenge of these endless, winding, uphill climbs. The shorter, exhilarating descents seem ever shorter. After four hours, with five substantial passes in the legs and the strain of being unacclimatised to the altitude, I am utterly shattered. But the scenery – huge peaks and hulking massifs all around – is genuinely epic.

At a crossroads, Franz offers me two choices: turn left, to cut the ride by around 30km; or right, to commit to the monstrous Passo Giau. At 19.9km long, with an average of 9.3 per cent gradient and 29 hairpin bends, it’s a prospect to give even the most seasoned cyclist the nerves. Two hours – and the expenditure of every ounce of energy and grit in my body – later, the challenge is complete. It is one of the most daunting of my stay, but it’s a bucket list-proportioned adventure.

The author and his Ferrari-red Pinarello bike outside the Rosa Alpina Affettato misto and fresh sourdough on the terrace of Rosa Alpina’s Wine Bar & Grill

On day two, my upper body gets a work out with an open-water lake swim. For this, we drive west, past the city of Bolzano, to a secluded private garden fronting onto Lake Caldaro. Diego, cool as ever, shadows me in a rowboat. With the sun on my back and the water at 21ºC, the 2km swim in millpond-flat conditions is exactly the welcome, physiologically balancing tonic it has been calculated to be. With every inhale, I glimpse the lush green of the surrounding fruit trees and snow‑covered peaks, aware the entire time it is a world away from the packed swimming lanes of the 25m indoor pool I’m used to.

Trail running is the other order of the day in these parts; for mine, I am joined by Pizzinini himself and his restaurant director and head sommelier, Lukas Gerges, on a fairly advanced circular route from the hotel. With the fatigue of the previous three days suffusing my legs – and evident in my gait – our guide, Samuele Majoni, a multiple title-holder here, keeps a just-gentle-enough pace and after a three-hour push, with a via ferrata thrown in for good measure, we head down a hidden valley to enjoy a lunch of crispy polenta, pork sausages and a cheeky Kaiserschmarrn in the sun at Scotoni, one of the Val Badia’s most loved mountain huts.

An early morning 2km swim in the waters of Lake Caldaro

Beyond the expert guides and training, the Rosa Alpina difference is in these indulgences. Each day holds the most welcome punctuation in the form of a long spa treatment: alpine herbal massages with anti-inflammatory arnica for muscle-pain relief, and Thai massages to work out stiffness. Refuelling is elevated to a whole different level: I am welcomed back after each excursion with homemade sourdough, speck and horseradish – a simple but delicious (and complex carb-rich) local dinner – typically followed by fresh pasta and local sparkling wine. The gastronomic highlight is St Hubertus, Rosa Alpina’s celebrated fine-dining restaurant. Norbert Niederkofler and his young team run a remarkably ordered kitchen, where at his butcher-block chef’s table I enjoy the first three of an 11-course menu, with wine pairings, that begins at 7pm and wraps up at midnight.

What makes the four days feel so special is this balance of limit-testing and indulgence. Exert, relax, repeat – to the extreme. A mountain high indeed.