Twenty-seven years ago, someone tried to stab Martin Bigmore while he was working as a police officer in Victoria.
After the incident, the then 29-year-old was diagnosed with post-traumatic stress disorder. He sought help and got better.
After 26 years without incident, Mr Bigmore had a recurrence of the disorder, possibly triggered by the approaching anniversary of his attack.
"After 26 years of no issues whatsoever, I had my PTSD return, and return at a level that has impacted pretty much all aspects of my life," Mr Bigmore said.
"Watching the news every night, brawls, violent assaults. I find very difficult to watch.
"I tend now to not watch the news, but it's hard to avoid it. We have mobile phones, news is around us everywhere."
Mr Bigmore said everyday life is changed because of the disorder's return.
"I can't work, home life, driving is hard, I have a medical team that supports me, medications, psychological treatment, psychiatric treatment," he said.
"Everyone's kind of working to help me to get to the best possible place. That's a long journey and we don't know when that will be."
The now 56-year-old has pulled on the gloves and entered the boxing ring to help researchers University of Canberra investigate how high-intensity exercise can combat post-traumatic stress disorder.
"I'm more than happy to do that, anything that might give me some personal insight to how to manage my PTSD and how exercise might be valuable in that regard," he said.
"More importantly, and in broader context how the outcomes of this study and any other studies along similar lines might benefit PTSD sufferers down the track."
The project will measure the effects of a boxing training session on biomarkers of the stress and inflammatory response.
These include saliva tests for the stress hormone – cortisol and heart rate variability, which provide insights into the "fight or flight" stress response. A second saliva test will look for signs of inflammation within the body by analysing the inflammation marker.
Honours student Katie Speer, who is leading the project said it was important to understand how the stress and inflammatory systems respond to and recover after exercise in individuals living with PTSD.
"Research shows that appropriate, regulated stress responses are important for health, but dysregulated stress levels which have been found in people with PTSD are associated with inflammation in the body," Ms Speer said.
"Inflammation has been associated with the development of chronic diseases, such as cardiovascular disease.
"By having our participants jump into a boxing training session we put their bodies under stress, and it's quite intensive exercise so we would expect to see changes in the stress and inflammatory biomarkers.
"Cortisol is a major player in our fight-or-flight response and not only plays a role in increasing our energy levels but also plays a role in the formation of memories."
The study is currently under way at the University of Canberra and the researchers are appealing for military veterans and first responders aged 45 to 70, with or without post-traumatic stress disorder.
"Personally, I'd like to get some insight into what a safe levels of exercise for me that help me manage my PTSD," Mr Bigmore said.
"Currently my sole strategy is just to go out and exercise at ridiculous levels, purely for piece of mind because during those periods I'm free from the thoughts that I have in my head."
People interested in joining the study can contact Dr Andrew McKune: firstname.lastname@example.org