A 90-year-old man is in critical condition after a nursing home left him sitting in the hot Florida sun for several hours on Wednesday.

The temperature in Naples reached a high of 93 degrees the day staff at Aristocrat Nursing home wheeled Robert Bernard outside at 2 p.m. and left him there for three hours, the New York Daily News reported.

Barnard was found unconscious when staff finally realized the wheelchair-bound man was left outside. He suffered a heat stroke, was dehydrated and had sunburn.

Nursing home staff and emergency responders tried to bring his body temperature down, which was 105 degrees, NBC-2.com reported. Experts say heat stroke can occur within an hour of being in the summer sun.

"The body actually shuts down and stores all that heat inside because it's lost its ability to sweat," Collier EMS Chief Walter Kopka told the station.

Paramedics could not lower Bernard's body temperature and he ended up having a heart attack at the hospital.

"It's very difficult sometimes to regain that breathing and the heartbeat because the body has been heated for such a long period of time," Kopka told the station.

On Thursday Bernard was still in critical condition in the intensive care unit. His condition on Friday was not immediately available.

It is not clear how staff forgot about the victim. The nursing home did not return the station's request for comment. 

Both the Department of Children and Families and the Collier County Sheriff's Office are investigating the Aristocrat Nursing home, which was investigated by the DCF at least once in the last ten years.

Families of the nursing home's residents were shocked by the news.

"I just can't see somebody wheeling somebody out and just forgetting them," Susan Parker, whose mother used to live at Aristocrat, told ABC 7.