There have been times after finals - notably after securing silver at the 2007 world championships - when he needed medical assistance because his mind and body disagreed on the location of his pain barrier.
He left Rowing New Zealand's programme post-Olympics for an MBA at Oxford University, a triumph in the 2009 Boat Race against Cambridge and a banking career at Morgan Stanley. Yet, as a self-made man, Bridgewater was prepared to sacrifice a "relatively comfortable banking job to do something extremely high-risk".
He came home to Cambridge with wife Rachel and their two children, started an enterprise called The Pure Food Co with brother Sam and business partner Maia Royal, and rebuilt his endurance on Lake Karapiro.
"The decision to return to New Zealand was not about having ticked off goals," he said.
"I was sitting at my desk and had this feeling I wasn't moving forward with something I was passionate about. I thought back to how I used to feel training, where you made a step forward every day. There's not too much luck involved with rowing.
"That was appealing to return to, and there was a sense of immediacy that I've only got one or two Olympics left. I could always go back to banking in my 40s or 50s but I still believe winning a gold medal is a real possibility.
"I've never really sculled before but, physically, I've come back to where I was on the erg [rowing machine].
"Technically, there are big holes but fortunately we have got good coaching from Mike Rodger. We sat down as a group and said if we want to do something New Zealand's never done before, we have to open our minds to change."
He compartmentalises his life between rowing, family and business, and knows the value of co-operation and empathy from those around him.
"[Wife and former national coxswain] Rach understands rowing demands and that I also need to earn a crust because I'm not at a stage where I'm earning PEGs [government-funded performance enhancement grants]. We have to make an effort and that's why Sunday becomes family day.
"Setting up the business was stressful initially but, while I'm only there three hours a day, it's generally quite productive. My business partners cover a lot of things I don't have to do.
"My coach had his own upholstery business in Cambridge and he also understands the demands of family life. The way the training programme is built now, the individual coaches have more autonomy which enables it all to work."
