Watching television with his kids or a simple weights session would bring on prolonged concussion symptoms for Tim Glasby, who has been medically retired form the NRL.
The representative forward had an emotional farewell with the Knights' playing group on Sunday and spoke of his concerns for the future that are impossible to ignore.
After repeated concussions over the years, Glasby only started to experience ongoing symptoms after his final head knock in a round-seven loss to North Queensland this year.
But after a 138-game NRL career plus five State of Origin games for Queensland, he had endured his fair share of knocks while rising through the ranks of the lower grades and park footy.
Those knocks, he says, never were treated seriously, even though the NRL is now leading the way in concussion treatment for contact sport.
The 31-year-old had experienced the symptoms in the past, for maybe a week at a time, but never over a prolonged period.
This time he was dealing with headaches, sensitivity to light and noise, motion sickness on the bus on the way to games - and it would all return worse when he overstretched himself mentally or physically.
"I was in a bad way for a bit, I couldn't spend time with my family or do anything like that so I just knew that was the time," he said on Sunday.
"It was scary, but I had the reassurance that I would recover from the symptoms that I was having and I haven't had anything for a little bit now.
"It was more frustrating and I felt a little bit useless and I couldn't do anything which wasn't nice.
"I didn't want to keep risking doing that."
In speaking to specialists he has been reassured his symptoms will not come back, but there are no guarantees about his future brain health.
The workings of brain injuries and how concussions can impact long-term health is still largely a mystery.
"In terms of the longer term ... there's some concern there definitely and that played into the decision of course, but they don't know enough about it to give a definite answer on it," he said.
"I suppose that's frustrating for the specialists that there's not enough studies done on it.
"I'm hopeful there won't be any issues."
Before joining the Knights he spent six seasons with Melbourne working alongside Adam O'Brien.
While he's been sidelined this season Glasby has been working with O'Brien in the Knights' coaching box and hopes to remain in rugby league in some way, as well as resume a career in financial planning.
"He's been enormous for me, not just in the box but over the last 10 years since I've come into contact with Tim," O'Brien said.
"I know the narrative is around the concussion stuff but he's a player who got absolutely every ounce out of his career.
"He finished playing under 20s with the Panthers and was told he wasn't going to make it, went home to Rockhampton, found his way to Melbourne and ended up a premiership-winner and representing his state.
"He's been a hell of a leader for this club."