Fittler had his squad in the pool at a Casuarina fitness centre in northern NSW on Thursday for a session with stress control specialist Nam Baldwin as they seek any advantage before their do-or-die clash with Queensland at Suncorp Stadium.

Baldwin is a regular go-to in Fittler's coaching plans, which also include as much of a focus on things such as meditation, barefoot walking or "earthing" and yoga as tackle bags and sprints.

The thinking behind taking his players under the water is to enable them to use breathing techniques to control things such as heart-rates and the body's response to stress.

It's hoped the lessons learned in the pool can be applied throughout the white-hot atmosphere of an Origin game.

"One of the only ways to calm ourselves down naturally is through the breath and when we're at a very high heart rate, trying to think your way out of problems is really tricky, but breathing your way out is so much easier," Baldwin said.

"One area is definitely when you're really gassed and you need to calm yourself down quickly.

"Second thing would be half-time, just getting into a calm state.

"Arousal is a huge factor of these guys' games, how aroused they get, so it helps them regulate their arousal pre-game.

"So sleeping better, all those factors comes down to self regulation."

Baldwin has worked with world champion surfers including Mick Fanning and Stephanie Gilmore as well as former tennis world No.1 Pat Rafter.

His methods are not all that new to rugby league players either with the Sydney Roosters a client and Blues' hooker Damien Cook says it's a practice he has found hugely beneficial.

"A few years ago, I took some lessons out of him and little techniques where we can get some oxygen real quick just through three good breaths whenever you can in a game," Cook said.

"It's intense times but you catch yourself in a small break, you try and grab some oxygen back in and calm yourself right down which will sure be important next week too."

Australian Associated Press