It generally just starts with being taken to the swimming pool as a kid.
I was sporty and my mum wanted to keep me busy, whether that was basketball or swimming or whatever.
But there comes a point in your life when your sport chooses you and, for me, it started to get serious when I was about 10 years old.
My mum would wake me up at 5:15 am and, I'm not going to lie, there were days I hoped she would sleep through the alarm. She never did.
I'd eat breakfast on the way to the pool and I'd do two hours training before school. "Chlorine boy" is one of the many names they gave me.
My mum never made a fuss and my older sisters never complained when weekends were taken up by swimming competitions. They got their revenge; these days they call me "golden boy."
But there were sacrifices, for both my family and me, and that will be the same for the current crop of elite swimmers.
The one that still haunts me 25 years on is missing my sister's wedding.
At the time, there was a competition that was offering money and we agreed as a family that I'd compete.
Looking back, did the money make much difference to my life? Maybe not but it seemed important at the time.
'It's hardly going down a coal mine'
As for other sacrifices, I have never looked at swimming like that.
I was 11 years old when I competed at my age group championships, winning five out of six events.
I looked at similar results in the US, China and Australia in the Swimming Times and compared myself to the fastest in the world, which was pretty cool.
And as I grew older and eventually turned professional, my morning starts, mercifully, became later -- 8am, which was very manageable.
And when people talk about sacrifices, I used to go to Australia every January for a six-week training camp. It's hardly going down a coal mine, is it?!
I didn't know any different. Swimming was the bubble I lived in and it was all I knew.
Okay, we beat our bodies up but that was out of love and passion for the sport, for your job. I genuinely loved it.
And that's the same for swimmers today. Much has changed from the early part of my career but a lot is still the same, too.
They still work in a four-year Olympic cycle and, outside of that, there are national, European and World Championships as well as the Commonwealth Games.
And the current generation still have the same goals. Much of the day-to-day stuff remains the same and is still every bit as grueling.
When I was younger, the training I struggled with most was swimming something like 60 or 80 kilometers in a week.
I had a short attention span -- I still do -- so that's why sprinting suited me. It also played to my physiological strengths.
I loved doing 25 or 50-meter sprints, then having a break before going back in.
I know long-distance swimmers think the sprinters are lazy because it looks like we're standing around the pool talking a lot. Sure, that did happen, but in between short, intense bursts.
Training on the track with a world-class hurdler
My obsession was doing anything to get quicker.
I would run on the track. World and Olympic champion hurdler Colin Jackson trained me for a time and I would run 200 meters in 25 seconds, not dissimilar to what I was doing in the pool.
Admittedly, there's a greater sacrifice involved in being a distance swimmer, pounding length after length of the pool -- or "counting tiles," as I used to refer to it.
I'm sure all distance swimmers would like to be sprinters but, if your body isn't made that way, there's not much you can do about it.
To me, all that mattered was 32 strokes in 21 seconds -- that's what my event was about.
So, I needed to get as much power as I could any way I could. But I had to balance being as strong as possible with being as light as possible.
As a kid, I was burning off so much energy I could eat what I wanted. As I got older, I ate a lot of protein, salad and vegetables, and not so many carbohydrates.
The idea of paying special attention to my diet
wasn't a thing for me. Eating healthily is a common thing throughout society now but that's what I wanted to do 20 years ago. It's how I am out of the pool now.
As for things like drinking alcohol and going out, there's still the chance for swimmers to do that.
We've seen some of the top names let their hair down. There's a break to go out, go on holiday and have some fun after one season ends and before the next begins.
The low points
Whatever you do out of the water, staying in peak condition is important.
Although I had some niggles in my career, I only had one major injury -- tearing the muscles under my armpit before the Olympic trials in 2004.
That's one galling part of being an elite sportsman or woman and there are some dark days as a result. That was one of mine, perhaps the darkest time as I failed to qualify for the Games.
And sports psychology is more prevalent now for when those dark times arrive.
I was always thought I didn't need a mental coach. They'd never stood on the podium so what could they tell me?
But, if it doesn't sound too strange, I did learn how to relax, how to not be so aggressive on my first strokes but to count them instead.
I appreciate that every swimmer is different but, for me, I always thought it was the best job in the world. And I wouldn't have changed it for the world.