"I really wanted to do it before the end of 2011 because I'd never done it before. I needed to see how I reacted as a practice run, to see if I wanted to do it again before London.
"The first three days back at sea level had a big effect. For instance when I tumble-turn, I don't take a breath until three strokes further to save time. At altitude I struggled to get those three strokes in but immediately afterwards I was managing seven strokes and it still felt easy." Regan says altitude provides no guarantees of success: "There is no documentation that says it will be the bees' knees. What it does guarantee is a wider fitness base to work from. It makes athletes more 'trainable'."
Altitude training increases athletes' red blood cell counts. Proponents claim that, when athletes travel to lower altitudes, they carry a relatively higher concentration of red blood cells for around three weeks. In theory this gives them an advantage; an increase in red blood cells means they can use oxygen more effectively and produce better times.
The camp was a key use of some of the $1.65 million in annual Sparc high performance funding. SNZ needs a medal and finals places at the Games to be considered for future Sparc funding as a targeted sport post-Olympics.
The inner turmoil of SNZ has not helped. It eventually saw a rejig of the board personnel and a decision to leave by high performance boss and former head coach Jan Cameron.
It is not a subject Regan dwells on: "I don't get involved in that. I deal with the people I have to. What I can't control, I don't worry about."
Boyle backs Regan's progress: "Mark is managing to create a team environment not felt before in [my experience] in New Zealand. It takes a while to get to know him but he is a great motivator, and his experience helps."
Boyle is back in New Zealand after completing a business degree at the University of California, Berkeley, in May where she swam in a largely sprint-focused squad under United States women's Olympic coach Teri McKeever. New Zealand has limited hopes of a pool medal in London but Boyle is the best bet. Just don't suggest this to Regan. He is fiercely protective.
"Lauren's no different to anyone else in my group. I don't want my athletes carrying an extra 10kg of public expectation into the Olympics. It is a process rather than being about medals. I don't give a rat's arse what people want, the only thing we can ask [of athletes] is for them to do their best.
"I just want to see them touch the wall, take their goggles off and smile because they have done a personal best. That's a gold medal to me every time.
"They represent their country and do the best job they can. You can't ask for any more than that and neither can I."
A decision on whether to have another altitude camp will be made once further assessments of the Flagstaff camp have been completed.
