Just one..more..lap ¦ten..more..seconds..With boot camp brain in full gear, urging myself to push harder than ever, I powered through Level 8 of the bleep test at 7.15am on Day One, wondering how on earth I would survive the week. At least I’m not the first one to stop I thought, glancing at the competition in the next lane as I felt my legs collapsing under me.

Although boot camps first originated across the pond in the USA with the aim of rehabilitating soldiers, prisoners and young offenders, today they’re designed to increase fitness levels, help tone bums and tums and lose weight fast, often with a little bit of time spent by the pool. At least that’s what I hoped as I boarded my Gibraltar-bound flight for New You Boot Camp in the rolling hills of Cadiz. Far from being some ghastly religious order-type regime (apart from the venue’s name, Hotel Monasterio, a former Spanish monastery dating back to 1592) this is New You’s flexible, luxury boot camp , the only one in the series which doesn’t impose endless hours of circuits if you prefer to use the time to de-stress and relax.

The exercise sessions at the resort, expertly arranged and co-ordinated by military PTIs (personal training instructors) are designed to cater to all levels of fitness and ability. When asked how we usually exercise, they didn’t seem impressed with my limp response: Pilates and Yoga? That’s not exercise! Oh yes, some of these guys have been in the Falklands so anything less than circuits and hill runs just won’t cut it. If you choose to participate in all sessions, it’s a full eight-hour day. The daily 7am cardio became most people’s favourite, and trooping triumphantly to breakfast after a rigorous early workout helped us get in the zone for the day ahead.

A typical day at boot camp involves early morning cardio, followed by a range of boxing, circuits and abs classes as well as bonding games of rounders and team activities such as Battle PT and SAQ drills where everyone drives themselves into the ground to avoid being outdone by the other team (warning: dismantling, moving and re-assembling water tank and wooden plank canon formations are fantastic workouts but should not be attempted at home). The hour-long sessions are not for softies and each is a real fight to the end, but the team remains encouraged and enthusiastic. Trust me, it’s more enjoyable with 22 of you building biceps and lunging in the sunshine to an ABBA soundtrack.

Fortunately, Spanish springtime hovers around the 20C mark (I attended the camp in April), so three agonizing but simply stunning half-day hikes in the Andalusian hills were led by local walking guides who proved extremely knowledgeable about the Roman and Moorish architecture of the area but less helpful on the kilometres of muddy swamps and cattle-trodden paths we encountered which almost resulted in lost trainers and twisted ankles. On the pampering side, although we struggled without a hotel spa and hot pool, lovely massage therapist Ange was on call to ease any aches and pains and many wouldn’t have made it through the week without her helping hand.

The hotel is a charming, quiet little enclave, deep in the heart of the countryside with the nearest village, San Martin del Tesorillo, a good few miles away. The 22 rooms are traditional and comfortable, with wooden chests, deep red drapery and icons adorning the walls. Grassy outdoor fields and landscaped courtyards provided a picturesque setting for sunset shuttles and the ornate banqueting hall became our boxing battleground. The ample pool, beautifully reflecting the towering palm trees was a great addition for recovery time. One tip: don’t pack any formal wear, evenings are best spent in shorts and flip flops enjoying a walk around the orange groves or huddled by the open fireplace with mugs of hot tea. The port and town of Sotogrande are a 20 minute cab ride away and worth visiting for a sneaky G&T and chocolate helado by the ocean if you’re not counting calories.

At New You Boot Camp, clients follow a delicious, specially-designed therapeutic diet but which allows just 1,200 calories a day for women and 1,400 calories for men. Larger portions are provided for those who don’t want weight loss, but there’s no dessert, coffee or alcohol in sight. Instead, just lots of caffeine-free tea and fresh lemon slices to detox. Although regional specialties such as chocolate churros and Iberico ham weren’t on our menu for the week, two cookery classes with talented chef Jake demonstrated how to make delicious, fat free alternatives to Winnie-the-Pooh style elevenses: healthy granola bars, creamy guacamole, and kiwi and banana smoothies. Lunches of paella, stuffed aubergine and fishcakes were healthy and filling, but a few more local seafood and fresh vegetable dishes for dinner wouldn’t have gone amiss, especially for vegetarians. However, informative nutrition presentations and one-to-one sessions offered a healthier guide to eating and re-established the difference between simple and complex carbohydrates that now seem to matter much more than they did in high school biology.

The results are evident after the first 48 hours at boot camp and as the full six days came to a close, we were all bright-eyed burpee experts. From the 18s to the over 50s, everyone was achingly well-rested and pounds had disappeared from the scale – ten pounds to the highest loser to be exact.*