Restrictive underwear and vertigo-inducing climbs were just some of the issues facing the team leaders on last night's Operation Transformation.
Viewers of the RTE show saw the five brave participants having to face their fears head-on as they dealt with an array of challenges for the weight-loss show.
First up was the gruelling job of climbing up a 100ft ladder, which saw them supported by members of Dublin Fire Brigade.
They all had to scale the top of La Touche House in Dublin's ISFC and then jump off the edge of the building.
As the participants got stuck into their gruelling new exercise and fitness plans, viewers watched team leader Yvonne Keenan-Ross struggling to find the right support - from her underwear.
She was filmed doing her exercises at home and looking frustrated, before whisking off her bra from under her shirt.
"I didn't realise just how resistant I am to exercise. I just couldn't do them," she said.
Despite her unorthodox approach to working out, Yvonne managed to shed an impressive 8lb, some 5lb more than her target.
Fitness expert Karl Henry said it was a "superb result" - but she needed to invest in a sports bra.
"Get the gear, get the water bottles, the sports bra is going to be a key component as it's a lot better than no bra - trust me," he said.
"If you're exercising properly you might be jiggling a little bit and a sports bra will just help contain things a little bit more."
Meanwhile, fellow team leader Sean Daly from Clondalkin was seen finally kicking his smoking habit before heading up to work.
Determined to get 2017 off to a healthy start, he was seen having his last cigarette but quickly struggled with his cravings.
"I do want to be off them but I'm struggling. It's tough going now," Sean said.
"If I crack and have one, I crack and have one but I'm hoping I don't though I'm not at that moment yet though."
He has also been cooking his first-ever meal, under the watchful eye of his mother, whipping off a dish of fish, peas and potatoes.
All Sean's hard work pays off at the end of the week as he sheds a massive 11lb.
Dr Ciara Kelly said it was proof that people can quit smoking and still lose weight.
"People say 'I can't give up the cigarettes because I don't want to put on weight'. Well you just gave up the cigarettes and lost 11lb at the same time," she said.