Shannan Ponton speaks about suffering from memory loss and extreme hypothermia on SAS Australia

Shannan Ponton has spoken candidly about suffering extreme hypothermia on SAS Australia.

On Tuesday, the 46-year-old said he still has no memory of completing a challenge, where the recruits were forced to endure a three-kilometre uphill hike in their wet clothes.

The former Biggest Loser star wrote on Instagram: ‘Hypothermia was brutal. Walking up the hill things went psychedelic. Then absolutely blank. Still no memory now.’

‘It was brutal’: Shannan Ponton (pictured) has spoken about suffering from memory loss and extreme hypothermia on SAS Australia

‘It’s like watching for the first time. At least we completed the task. Having the kids in my thoughts got me through,’he continued.

‘Having low body fat worked against me. Time to fatten up,’ he ended.

During Tuesday’s episode, a focus challenge proved to be too much for Shannan and he began to show worrying signs of hypothermia.

Following a helicopter jump into freezing cold waters, the recruits were then forced to endure a three-kilometre uphill hike in their soaking wet clothes.

Reality: Shannan shared a photo showing his weight-loss and wrote: ‘Hypothermia was brutal. Walking up the hill things went psychedelic. Then absolutely blank. Still no memory now’

But the 46-year-old former Biggest Loser trainer slowed right down and struggled to put one foot in front of the other, moaning as he walked.

After making it to the top of the hill, chief instructor Ant Middleton told the recruits to quickly change into dry clothing, as Shannan shook uncontrollably.

While the other recruits quickly stripped off, Shannan appeared disoriented, as the concerned DS (directing staff) watched on.

Life or death: During Tuesday’s episode, a focus challenge proved to be too much for Shannan and he began to show worrying signs of hypothermia

Sensing something was wrong, Ant stepped in and proceeded to help Shannan get changed into warm clothing.

After piling into the back of a truck, he continued to moan, as fellow recruit Firass Dirani tried to get him to take hold of a hot drink.

Arriving back at the camp, a slightly warmer Shannan confessed that he had no recollection of the last part of the challenge.

Warming up: After piling into the back of a truck, Shannan continued to moan, as fellow recruit Firass Dirani tried to get him to take hold of a hot drink