Pinched, poked and prodded — that's what one Brisbane man regularly volunteers for by offering up his body in the service of medical research.
Since retiring, grandfather Des Calthorpe uses his free time to help medical researchers with human clinical trials.
Mr Calthorpe began dedicating his time to research after hearing an interview on his local ABC radio station.
"A professor was talking about a study he was doing about how exercise can grow new brain neurons.
"They had done the study with mice but then they wanted to undertake human trials so I thought 'why not?'
"It involved exercise three times a week at University of Queensland (UQ) at the same time they were doing brain tests, and it was really interesting."
He said that spurred him on to sign-up for other trials.
"I'm about to go through my 21st research study in the last two years so I am the human guinea pig now," he said.
Testing in a cold room
Mr Calthorpe had done trials with the Queensland Brain Institute at UQ as well as Prince Charles Hospital Foundation.
One of the most interesting tests involved being locked in a cold room.
"I was in shorts and a t-shirt and they locked me in a room for two hours and turned the temperature down to 10-degrees and put a fan on me," he told ABC Radio Brisbane.
"I was told that for the first ten minutes I would shiver but after that I would be fine.
"When 10 minutes came up I thought 'great I'm no longer shivering this is fantastic', but it only lasted for 30 seconds and then for the next two hours I shivered."
The researchers were looking at the effect paracetamol had on older people and body temperature.
"If your [temperature] lowers too much you can risk hypothermia," he said.
"When you get older you pop more paracetamol and [the researchers] wanted to see the effect it has."
'Probe stuck up my rear end'
Some of the testing involves more discomfort than just shivering.
During the tests Mr Calthorpe is often has multiple vital signs monitored.
"I'm never just sitting there, I have an oxygen mask on so they can measure oxygen levels, and you're constantly having your blood pressure taken," he said.
"I've also had a probe stuck up my rear end to take my core body temperature."
He said all the studies must pass safety and ethical standards before the human trials start.
One test involved food — but it was not quite what Mr Calthorpe expected.
"I thought there would be gourmet food everywhere, but researchers had 24 eye-droppers with clear fluid in them," he said.
"We had to put them on our tongue to tell them if it was salty, sour or sweet."
'A great deal of satisfaction'
The former hardware store owner originally thought that after retiring he would jump straight into travel, but it has been put aside for a moment.
"We will travel, but I had worked for so long and in my field, I never had time for hobbies," he said.
"I wondered what I would do, but then [clinical trials] came up and now I can't keep up with them."
He said he liked knowing he was helping others.
"I really do get satisfaction out of knowing that I'm doing something that might help people with dementia or Parkinson's," he said.
"Most of the ones I have done have been with the Queensland Brain Institute.
"There's not a great deal of personal benefit, it's more satisfaction in knowing that in the long run I'm helping people."
