An investigation has been launched following the death of a bodybuilder who lay unconscious under a cold shower for 15 hours before he was eventually discovered.

Giuliano Pirone was training at a 24-hour gym in Perth, Australia, before tragedy struck on 20 August this year.

The 33-year-old began to feel unwell during his workout and is believed to have headed towards a shower cubicle before he suddenly collapsed at around 7.30am that morning, according to reports.

It wasn't until a whopping 15 hours later when police broke down the bathroom door and found the father-of-one slumped on the shower floor under cold running water at around 10.30am.

Giuliano's family had raised concerns about his welfare earlier that day at about 3pm. Police then used the signal from his mobile phone to find him.

According to ABC News, the fitness fanatic suffered a brain injury and never regained consciousness.

Giuliano passed away at a hospital in Joondalup around two weeks after he was found passed out under the shower.

On Tuesday (8 October), WorkSafe WA - the health and safety regulator for general industries, mining and petroleum sectors in Western Australia - announced it had launched a probe into the bodybuilder's death.