A 61-year-old from Bletchley drowned on Friday, after suffering a ‘medical episode’ when he retrieved a ball from the water in the Blue Lagoon.
It is believed the man, who has not yet been named, died at the lake behind Water Eaton, Bletchley, at around 6.40pm.
He was the fifth person to die in open water in the UK last week, including two teenagers in Buckinghamshire and Bedfordshire, as people used lakes and rivers to cool down during the heatwave.
The man was treated by paramedics after being pulled out of the water by a member of the public, but he was declared dead at the scene.
Police had cordoned off an area at the site while they carried out an investigation to determine the circumstances leading up to the man’s death, which is not being treated as suspicious at this stage.
Following the drowning, Detective Inspector Matthew Darnell renewed warnings about the dangers of venturing into open water.
He said: “This was a tragic incident, which has led to the sad loss of a life and our thoughts are with this man’s family at this time.
“We would urge people to be aware of the hazards of getting into open water such as lakes, reservoirs and rivers, no matter how tempting it must be in the hot weather.
“Open water can contain hazards and unexpectedly cold water can catch bathers off guard.
“Inland waters can be very cold no matter how warm the weather is which can lead to cramp and breathing difficulties so we would urge people to take great care and be aware of the dangers before going in.”
Councillor Mohammed Khan, who represents Bletchley East, said: “I was very sad to hear a man had died.
“I would like Milton Keynes Council to look into this very carefully and make sure it does not happen again.
“It is a lovely place to visit, especially for families during the summer holidays, so perhaps we could look into putting more signs up to warn people about the dangers.
“People’s safety comes first.”