The fitness challenges only masochists would dare try

There’s hardcore, then there’s a five-day, 315km mountain trek across the mountainous spine of Wales, with 15,500 metres of ascent. No, that’s not a typo – you’ll be hiking up almost 41 times the height of the Empire State Building, for “fun”, apparently. The pain is worth it, though, to be part of such a legendary event. Along the way, you’ll tick off Wales’s most famous mountain ranges and peaks, including Snowdon, Cadair Idris and the aptly named Black Mountains (them again). Many have tried, many have failed: hence why it’s known for being one of the toughest fitness challenges out there. Indeed, even the most experienced mountain runners will have to dig deep to reach the finish line.

2-7 September; dragonsbackrace.com

Wildswim in Ireland

New to wild swimming? Go paddle in the shallows. Taking place in the beautiful (if chilly) waters of Ireland’s Killary Fjord, participants must tackle a gruelling 3.9km swim. It isn’t the distance alone that will sap your strength, though; temperatures can be as low as 12 degrees, even in summer. Prefer to dip your toe in? There are a few shorter courses to choose from, including a 2km and a 750-metre race. Wetsuit optional (or so they say).

14 September; gaelforceevents.com

Swim the Serpentine