A man found at the bottom of a public swimming pool in Northamptonshire died of natural causes, a coroner has ruled.
Adnan Ansari, 32, was pulled from Wellingborough Swimming Pool after he was spotted by a young boy.
Despite resuscitation attempts, he was pronounced dead shortly afterwards on 10 August last year.
An inquest at Kettering Magistrates' Court heard Mr Ansari, a security guard, died of Sudden Adult Death Syndrome (SADS).
Lifeguard Kate Glasspool told the hearing a young boy drew her attention to Mr Ansari, who worked at a Sainsbury's distribution centre at Pineham, near Northampton.
Dragged from pool
She said he was at the bottom of the deep end, which is about two metres (6ft 6in) deep.
She asked a colleague if they thought he was just holding his breath, then decided to get in.
"I knew something was wrong when I first touched the male. There was no reaction at all," she said.
She pulled him to the surface and dragged him to the side of the pool, where she and other lifeguards tried to carry out cardiopulmonary resuscitation (CPR), the inquest heard.
Fellow lifeguard Joel Bonaobra described trying to resuscitate Mr Ansari, of Alma Street, Wellingborough, after he was pulled from the pool.
"In my experience I don't think this person drowned because people who start to drown obviously shout, splash about - the fear of death takes over and they seek help," he said.
Pathologist Dr Kevin West, who carried out the post-mortem examination, said Mr Ansari had possibly died of an inherited heart condition called Long QT Syndrome.
He said electrical disturbances in the heart were often documented as SADS and gave this as the cause of death.
Northamptonshire coroner Anne Pember said: "I do believe from what I have heard that the lifeguards acted promptly and appropriately but sadly when he was taken from the pool there was nothing that could be done.
"The cause of death was not drowning. It was natural causes of cardiac origin."