It's something I'll never forget - collapsing at the end of the single sculls final at the 2008 Beijing Olympics after losing about 4kg the week before from a gastrointestinal virus. I battled my way to a bronze but was so dehydrated that, to this day, I don't remember the last 100m.
The virus had caused me to lose a significant amount of fluid and that had a devastating impact on my performance.
My thirst for gold started when I watching American track and field athlete Carl Lewis win at the 1988 Olympic games. I loved and tried most sports at school, but was never good enough to realise my dream.
I had all but given up on making the Olympics until that fateful day I started rowing for fun at university.
I've dedicated myself to achieving my Olympic dream ever since.
As athletes, we dedicate so much of our lives to training and getting our bodies in the best condition possible to compete, but without the correct hydration we're effectively running on empty. My experience in Beijing is the ultimate example of this and is why I agreed to be a Powerade Olympic Games ambassador.
During an average race, I can lose anywhere between one and three litres of sweat, depending on the conditions. Temperatures in Rio this month are forecast to reach up to 32C, a far cry from the frosty mornings on Lake Karapiro we're used to. We've recently been stationed in Europe as part of our acclimatisation and arrived in Rio last week to get used to the local conditions.
A typical race day starts with the alarm going off about 5am.
We have a quick breakfast before catching a bus to the venue for an early warm-up. We then head back to a day house near the venue for a second breakfast and, if I'm lucky, I try to squeeze in a nap to relax the nerves before heading back to the course about an hour before the race.
From there I stretch and do one last warm-up on the water about 30 minutes before the start gun.
Unlike some athletes, I don't have a pair of lucky socks or the same pre-race meal to get me in the zone, but I do listen to music. You'll find anything from the Rolling Stones and Dire Straits to Eminem on my playlist.
From that point on we have to trust that our training and preparation has put us in the best possible position to win gold. I've come to learn that, no matter how nervous you feel in the build-up, the second that start gun fires the nerves will disappear. Part of that trust comes with knowing we've fuelled our bodies with the right stuff to really hit our stride.
I left the Beijing Games a changed athlete. I learned the bitter taste of disappointment and missed chances. No matter how you envision a race playing out, sometimes you just can't avoid that curveball. It's about how you deal with the curveballs that matters most.