Los Angeles: The inside of a car parked in the sun can reach temperatures of 46 degrees Celsius in just an hour, and could prove fatal for a child trapped inside, a study has found.

On an average, 37 children in the US die each year due to complications of hyperthermia - when the body warms to above 40 degrees Celsius and cannot cool down - after being trapped in overheated, parked cars.

Researchers from University of California San Diego and Arizona State University found that if a car is parked in the sun on a summer day, the interior temperature can reach 46 degrees Celsius. and the dashboard may exceed 73 degrees Celsius in approximately one hour - the time it can take for a young child trapped in the car to suffer fatal injuries.

The study, published in the journal Temperature, compared how different types of cars warm up on hot days when exposed to different amounts of shade and sunlight over different periods of time.

Researchers also took into account how these temperature differences would affect the body of a hypothetical two-year-old child left in a vehicle on a hot day.

"Young children are vulnerable to the impacts of extreme heat with increased emergency department visits found during heat waves. Internal injuries can begin at temperatures below 104 degrees (40 degrees Celsius)," said Jennifer Vanos, assistant professor at UC San Diego.

"Compared to adults, children have a quicker rise in core temperature and a lower efficiency at cooling," said Vanos. Researchers used six vehicles for the study: two identical silver mid-size sedans, two identical silver economy cars and two identical silver minivans. PTI