"I'm just so happy I made it through another day."
That is the answer Erin McNaught would give when the instructors on SAS Australia would ask her why, after hours of grueling physical and psychological challenges, she was still smiling.
The 38-year-old actress, model and TV presenter is one of the stars who signed up for Channel 7's boundary-pushing reality show, where celebrity 'recruits' are put through the Special Air Service selection process.
The filming process saw Erin and her fellow recruits be put through extreme physical endurance challenges, sleep deprivation and interrogation by an elite team of ex-Special Forces soldiers.
The experience was so intense that even though filming has now wrapped and Erin is back at home with her young family, she still bears the emotional and physical scars from SAS Australia.
"Just before the very first episode of SAS Australia aired I was watching the teaser trailer that came out on Instagram," Erin told Mamamia's entertainment podcast The Spill.
"We were having people around to watch the first episode and I was just cleaning the house vehemently and then I paused and just collapsed on the bathroom floor.
"I was sobbing like a little child because up until that point I was just so immersed in what an incredible experience it was to film the show, that I suppressed a lot of the trauma I went through.
"When you’re watching it on TV you get transported back to those moments, feeling everything you felt at the time.
Listen to SAS Australia star Erin McNaught talk filming, feuds and death scares on The Spill. Post continues after podcast.
Unlike other reality TV shows where contestants are only in danger of leaving with a broken heart or a slightly battered reputation, SAS Australia recruits are left recovering from intense physical injuries.
"Physically... I am getting there," Erin said when asked how she is recovering from filming. "I have some pretty bad bulging discs in my neck, which are really s**tty and causing me a lot of pain. I also tore a ligament in my sternoclavicular joint, which is where your sternum meets your collar bone. And I tore my subscapularis which is one of your rotator cuff muscles. So one of my arms was pretty useless for six weeks.
"It’s just such an intensive amount of physical activity in such a short amount of time. You’re up at 6am and from the moment you get up to the moment you crash into bed at 11pm when they turn the lights off, you’re on your feet being active."
In the opening scenes of the series, Erin and her fellow celebrity recruits were tasked with falling backwards from a helicopter into the water. A stunt she says left her "feeling like I'd been hit by a truck" and caused her to blackout while underneath the water, left her with two black eyes and blind in one eye for several hours.