An inquest's heard how a former mayor of Cambridge who died on a scuba diving holiday with his wife in South Africa had an undiagnosed heart condition.
Experienced diver Nigel Gawthrope, 61, was on his second dive of the day when he indicated to his wife Jenny that he wanted to come up, a hearing in Huntingdon was told.
He was taken aboard the dive boat and given oxygen, according to a report by pathologist Dr John Grant, read out by Cambridgeshire area coroner Elizabeth Gray.
Mr Gawthrope was given CPR, the boat returned to the beach and emergency services were called but he died on January 11 2019.
Police in South Africa said there was no foul play.
A post-mortem examination carried out in the UK, after Mr Gawthrope's body was repatriated, recorded his medical cause of death as acute left ventricular failure, contributed to by ischemic heart disease.
An initial post-mortem examination, carried out in South Africa five days after his death, found air bubbles in the ventricles of the heart.
But Dr Grant said there was "no information on how the body was stored" for those five days and that the act of decompression can lead to gases in the body which may not have been present at the time of death.
Ms Gray said she accepted the findings of the UK post-mortem examination and said that Mr Gawthrope "wasn't aware he was suffering from anything significant".
She described diving as a "physiologically challenging activity for anybody, but for somebody with undiagnosed coronary artery disease it was just too much".
She said Mr Gawthrope's heart condition was "unknown, undiagnosed" and that there was "no evidence to suggest there were any other indicators that he shouldn't have been diving on that day".
Ms Gray said diving was an activity Mr Gawthrope "clearly loved", and she told his widow: "I urge you to think about those really happy times that you had together."
Mr Gawthrope was eight months into his term of office as mayor of Cambridge when he died in Umkomazi, near the city of Durban.
His wife said he worked as a college porter and was previously a book binder. She said he had a "zest for life", describing him as having "strong socialist principles" and that he was "dedicated to trade unionism".<
"He may not have been hugely well-organised but what a life I had with him," Mrs Gawthrope said.
"Nigel brought so much life and colour to everything I did with him."