I've never been one for New Year resolutions but I started the year 2012 by deciding to make two major changes in my life - one was to get physically fit (or certainly fitter than I am now) and the other was to considerably improve my spoken Thai. I must confess that it took me until well into April to implement the first part of my plan, but I've done it - I've finally joined a gym.

For most of my adult life and certainly all through my teens, I was, as my Dad used to say, "built like a well-kept grave". You've heard about the bloke who sent off for a Bullworker and couldn't get the box open. You've heard about the guy who took his shirt off and there were at least six places you could hang a coat. Well that was me.

I was skinny right up until the day I got married at the age of 40. Then Mother Nature and middle-age started playing cruel tricks on me and I began to pile on the weight. I didn't feel as though I was eating more or spending more time horizontal on the sofa, but I finally started to fill out. The problem was - as many middle-aged men will testify - that fat tends to accumulate in all the wrong places, most noticeably the stomach area. Suddenly there were holiday photos where my head resembled a waterlogged potato. Something had to be done. It's just a shame that it took me a further eight years to finally realize it.

Much of my inspiration has come from my pal Andy up in Chiang Mai (who I may have mentioned in previous blogs) Andy is fanatical about staving off the onset of ageing, especially now he's reached the big five-o himself. Barely a day goes by when Andy doesn't grab his faithful old stick from behind the door and head off for a couple of hours of power-walking up Doi Suthep. Then he'll finish off with a disgustingly healthy meal of veggies and brown rice at the local temple. I accompanied Andy on one of his power walks a few months back. When we descended the hill after a long meander through uphill forests, Andy was ready for a fruit shake and a rye bread sandwich, I was ready for thirty minutes on a life support machine.

Andy is also a mine of terrifying health information, most of which he gets from the internet and most of which he's only too happy to share with his unfit friends.

"Do you know what I read the other day Phil?" said Andy. I knew whatever was coming was not going to brighten up the day one iota. "The body begins to age at twice the normal rate once you reach your late 40's. Think about it Phil. Twice the normal rate until the day you die"

Thanks Andy. I thought you were a friend.

But I knew deep down Andy was right. I was spending far too much of my time stagnating in front of a computer. I couldn't even remember the last time I did any proper exercise.

Unfortunately, what I don't have are large open, verdant spaces in which to power-walk, jog, run, hop - or whatever it takes to get the blood circulating around the body and the heart pumping that little bit faster. If I was going to get in shape, it would have to be a gym.

Gyms - in fact the mere mention of the word - have always terrified me. What instantly came to mind? How about gorgeous, lithe females in leotards and legwarmers doing twenty kilometers on a treadmill purely as a warm-up or great big muscle-bound hunks parading naked up and down the men's locker room with ginormous wing wangs flapping in the breeze? And let's not forget the steroid-guzzling Terminator, lifting the equivalent of a fully-grown African rhino as everyone stands around cheering and copping a crafty feel of his fully flexed biceps.

It's a world I've never felt any association or affinity with. In fact I've always considered the body-builder physique to be ugly. I remember in my youth, reading comics and magazines and seeing the famous Charles Atlas advert with a ripped guy standing on the beach and shouting "Come on in girls, the water's lovely!" in the direction of a couple of giggly blondes stretched out on their sun-loungers. That was never ever going to be me. I can't even fuckin' swim.

But you get to a point where you gaze at yourself in the full-length mirror - and I'm not talking about in your wife's underwear when she's gone out shopping - and think "Phil, that stomach's got to go"

I guess it was pure fate, but a swanky gymnasium and spa complex recently opened about five minutes walk from where I live. Several of my wife's work colleagues had already become members and they fed her with glowing reports. "There's even a saltwater swimming pool and free yoga classes" they said.

Joining up then became the easy part. The wife and I gritted our teeth (if I was going to suffer, then I was determined she was going down with me) and we both went along to see what this gym lark was all about. I was pleasantly surprised. People of all shapes, sizes and ages were battling with futuristic-looking weight machines and dare I say it - it even looked like good fun. I got an overwhelming sense of ‘well, if they can do it, then so can I' Sign me up. And yes, I'll have 30 hours with a personal trainer as well.

A few evenings later, I met with Khun Chin, my personal trainer, for the first time. He looked nervous (he'd never had a farang to take care of before) and I'm pleased to report that I physically towered over him. He looked like a strong wind would blow him over. Yes, he was firm and well-toned but not as big as some of the other trainers I had seen ambling around.

We started with him checking my weight, blood pressure and body fat content, then he wanted to know all about my goals. I didn't really need to say anything. He only had to take one look at my skinny legs sticking out from under a pair of nylon shorts and my biceps like two knots in cotton. This definitely wasn't rocket science. "I think I know what you want" he said "you want to build up your arms and legs and flatten that stomach into a six-pack"

"Errrr....that would be nice" I said, sounding like I'd agreed to have a custard cream with a cup of tea at my grandmother's house.

At this point I was introduced to my wife's personal trainer - a cute-looking tomboy by the name of Khun Lee. She looked me up and down and said "actually I think you've got a fantastic shape for a guy of 48"

I knew it wasn't a flirtatious comment because she obviously batted for the pink team. But then as I glowed with pride and drank in Khun Lee's admiration, she added "apart from your belly"

Anyway, to cut a long story short, I've now had eight sessions with the personal trainer and I'm chuffed with the progress. I can run five kilometres on the treadmill without feeling like I've got the lungs of a 90-year-old ex coal-miner, and I can feel the improvement as well as visibly see it in the mirror. And Khun Chin the PT, despite being shy and lacking in confidence at first glance, has taken on the persona of the drill sergeant from Hell. He pushes and motivates me like I've never been pushed and motivated before. I just wish he wouldn't stand beside me while I'm quenching my thirst at the water cooler and say "water is for pansies. When you're finished, shall we go out and pick some flowers? You'd like that wouldn't you you big pansy? Now get back on that weight machine and give me another two sets"

OK, I'm only kidding. But there are no half measures with this guy. I wouldn't summon up the motivation and the reserves without him that's for sure.

As a final thought, it's interesting to note how obsessed you can become with all this gym and fitness malarkey. Every day that I don't make the gym - even if it's for a half-hour workout on the rowing machine - I feel like I'm betraying my body.

The refrigerator is now stocked up with organic fruit drinks and cereal bars where once there was just fizzy pop and half a box of donuts. I've even been chatting to my ex-boxer, fitness-fanatic uncle in the UK about abdominal crunches and lower deltoids (I'd always assumed they were a region in Africa)

I'm embracing the new me. And while I'll never be getting a call from Hollywood because Sylvester Stallone needs a stunt double, I'm certainly seeing the benefits of a regular exercise program and beginning to see what all the fuss is about.