Man critical after Brisbane gym incident

A man has been rushed to hospital with significant injuries to his head and chest after an incident involving weights at a Brisbane gymnasium.

It is unclear exactly what happened, but it appears the man was struck by a weight just before 6am (local time) on Thursday, Queensland Ambulance clinical director Lachlan Parker said.

"His injuries were very severe, so we dispatched two crews, including a critical care paramedic," he said.

Bystanders began first aid before paramedics arrived. The man was later transported to hospital.

He is estimated to be between 25 and 35 years old.

"He was, like most people, just working out in the gym ... and for whatever reason ... a weight has fallen on his body and he suffered serious injuries," Mr Parker said.