A fit and healthy police officer who ran marathons died of a heart attack seven hours after completing a standard GMP 'bleep' fitness test, an inquest heard.
Detective Constable Quamar Zaman, described as 'exceptionally popular' and 'the ultimate professional' by his force bosses, was just 38.
His family said he didn't smoke or drink and had no underlying heart conditions.
A coroner recorded a conclusion of natural causes and called the 'well-respected, will-liked and modest' officer's death 'a very tragic case'.
DC Zaman - who was known by friends and family simply as 'Q' - joined Greater Manchester Police in August 2009, working in the Rochdale division.
He was assigned to the Middleton neighbourhood police team in June 2010 then joined the counter-terrorism policing unit north west at GMP headquarters in 2016, where he remained for the rest of his service.
The inquest at Rochdale Coroner's Court heard DC Zaman, from Bury, completed the test, part of the force's annual refresher fitness training for officers, at 8am at a Territorial Army barracks in Stockport on March 25 last year - and passed with no issues.
He completed a medical questionnaire which addressed heart issues among other health-related queries beforehand and signed a declaration that he was fit to train, the court heard.
PC Alex Merrett, a GMP trainer, said DC Zaman, an IT university graduate, was in a second wave of officers to attempt the shuttle-run test. There were 24 in total on the course.
Giving evidence, he said there was nothing to suggest that DC Zaman wasn't physically fit.
"He passed the test," said PC Merrett. "Everybody said they were okay. He seemed fit and healthy."
But the inquest heard around 50 minutes later, DC Zaman left a PowerPoint presentation being held in a room upstairs and walked downstairs to an office.
There he told PC Ian Holt, the lead trainer, that he had been sick and complained of shortness of breath, the inquest heard.
PC Holt, in a statement, said DC Zaman was speaking clearly and coherently and there were no other symptoms displayed at the time.
"He presented as fit and healthy," he said.
Regular gym user DC Zaman, the inquest heard, was escorted to the car park where he said he was 'feeling fine' and was fit to drive home, officers said.
"He said he was feeling fine," added PC Holt. "He said he would call his supervisor.
"He was not out of breath and was speaking coherently as he was walking to the car."
The court heard 'welfare checks' were ordered by the force to be carried out on him that day.
Sgt Pete Hurst, from GMP's Personal Safety Training Unit, said if PC Holt had any concern, he was sure he would have called for an ambulance.
Ifda Zaman, DC Zaman's sister, told the inquest her brother set off for the fitness test at 6am. He had two bananas and took his lunch with him, she said.
She said he drove back to their mother's home, where he said he was struggling to breathe and that he had been sick in a bathroom.
Ms Zaman said her brother complained his shoulders and arms were hurting, and of chest pain and tightness, before an ambulance was called.
He arrived at Fairfield General in Bury at 11.08am and had an ECG - an electrocardiogram to check a heart's rhythm and electrical activity - within eight minutes, but no signs of a heart attack were spotted, the coroner was told.
A doctor, the court heard, said he believed the issue may have been 'muscular -skeletal pain' from the exercise.
The inquest heard blood was taken from him for testing and a repeat ECG was ordered to take place within 30 minutes.
But the coroner was told the second ECG, which did show a heart attack, didn't take place until 1.05pm, at the same time as the results of his bloods came back. DC Zaman was then transferred to a 'green' coded resuscitation room.
The hospital's A&E unit was busy at the time and a healthcare assistant couldn't find a room to complete the second ECG in, the inquest heard.
But Dr Ritesh Shetty, the clinical director of Fairfield General, said even if the second ECG had been performed within 30 minutes, 'it is likely' that the heart attack wouldn't have shown up then.
Coroner Catherine McKenna said she found it 'more likely than not' that DC Zaman 'started to suffer from the heart attack' at 12.40pm, a time he complained again of chest pain.
The inquest heard DC Zaman, a classic car enthusiast, was due to be transferred to Manchester Royal Infirmary for a specialist heart procedure and an ambulance was called.
A cardiologist at Fairfield could have performed the surgery there, but he was treating another patient at the time, the coroner was told.
At 1.50pm, 45 minutes after the second ECG, the inquest heard DC Zaman became 'unresponsive' and was witnessed by a doctor 'in the process of collapse'.
He went into cardiac arrest at the same time the consultant who could have performed the specialist surgery at Fairfield became free, the inquest heard.
Attempts were made to resuscitate him but sadly, he was pronounced dead at 3pm.
The coroner, Ms Mckenna, said she was satisfied the 'outcome would not have been different' had DC Zaman been taken to hospital directly from the barracks where the fitness test was held, or if he had the second ECG earlier.
She said DC Zaman suffered a 'mechanical failure' of the heart.
A medical cause of death was given as myocardial infarction - a heart attack.
"This has been a very tragic case," said the coroner.
"Constable Zaman was a fit and healthy man who served the public in his role as a police officer. He was a much-loved son and brother."
Dr Shetty said the hospital trust ordered a 'root and cause analysis investigation', from which a number of 'action points' and issues emerged.
He said the A&E team was 'shocked' by his death, adding: "It was, unfortunately, something that could not have been predicted."
Assistant Chief Constable Dominic Scally, of Counter Terrorism Policing Unit North West, said: "Q was a dedicated officer and popular member of the team; he was the ultimate professional and an incredible officer, able to engage with everyone at all levels of policing.
"It was a privilege to have him as part of our team and he is sorely missed by everyone and will be forever in our memories."
