'I would last one minute': 2011 World Cup winner reveals physical and mental health struggles

Former All Blacks halfback Piri Weepu has opened up about his struggles with mental health during his playing career, saying he battled through periods of "bad thoughts" and self-harm.

Weepu, who played 71 tests for the All Blacks and was a member of the World Cup-winning side in 2011, is one of many All Black greats involved in Three's Match Fit, a documentary series that challenges a group of former players to get back into shape, both physically and mentally, before one last game against old rivals.

The show is an inspiring story of health, fitness and brotherhood, through the lens of rugby.

One of the most powerful segments from the show came during the third episode where Weepu spoke about his struggles with fitness and mental health during his career.

"My fitness during my prime was s***," Weepu admitted. "I'd probably say I was one of the slowest halfacks around. If I was to start in the game right now, I would last one minute. I'll do two sprints and I'll be buggered – absolutely shattered. And I'd be asking for Ted (Graham Henry) to be subbing me off."

The 37-year-old said he also went through some tough times mentally while playing.

"I have battled with mental health," he said. "It's just having these bad thoughts. I was actually doing self-harm and that. Yeah, I was just drinking to try and mask the thoughts that were going on in my head."

"This was all while playing too so it was pretty difficult to focus," he added.

"But I had a book that I wrote in and that was me trying to get rid of all those thoughts I had in my head and then burn it so I didn't have to read it. I figured out that I need to have a process for myself. You've just got to find something that you love.

"Hopefully at the end of this, I can continue to be a bit healthier and spend more time watching my kids play their sports."

On the stroke he suffered in 2014, Weepu said: "I started talking like a baby. The boys were looking at me like, 'Eh? What's this guy up to?' In my head I thought I was talking normal."

The stroke was eventually traced to a blood clot in the part of the brain that controlled speech, he explained.

Weepu says he still has issues with sleep, having suffered cartilage damage in his knees and a broken nose which means he has to sleep on his side.

Like many of the former All Blacks featured on the show, Weepu hopes to take up the challenge to continue his journey towards mental and physical health.

Match Fit airs on New Zealand's TV Three every Tuesday at 7.30pm.