"extreme hobby" is a correct and usable phrase in written English.
You could use it to describe a hobby that is relatively uncommon, particularly dangerous, or otherwise extreme. For example: "Skydiving is an extreme hobby, but one that some people find both thrilling and exhilarating."
"In Japan, we're finding you have more of an audience of people who understand the urge to have an extreme hobby," Martina said.
Storm chasing has long been an extreme hobby, and it has been spotlighted in recent years by the Internet, which allows semiprofessional chasers to share videos and even live-stream their trips.
I thought I knew my body well - in fact, taking care of it was an extreme hobby of mine.
Learn an extreme hobby practice things like jumping certain heights even wheelies on bikes or skids are a good way to show extremeness.
Extreme hobbies lead to extreme places.
Urban Exploration (also called Urbex or simply UE) might be one of the most extreme hobbies that exist.
He had taken up an unusual hobby: performing extreme acts of salvage on objects damaged by the storm.
Kopatchinskaja dominated the second movement with everything from broad, double-stopped melodies to stratospheric yelps and glissandi: when Larcher leaped on stage to join the ovation for his soloist, the London Philharmonic, and conductor Markus Stenz, one remembered that his hobby is extreme rock-climbing: this work dealt in just that sort of danger.
As interest in food and drink continues to skyrocket, the phenomenon has kickstarted an unusual offshoot -- extreme food and drink hobbies.
Those cases inspire tactics that are turning the once-staid pursuit of genealogy, perhaps second only to gardening among American hobbies, into an extreme sport.
But while they never took boxing to an extreme – enjoying it first as a hobby and later as entertainment – their rebelliousness did spiral out of control and led them to become ruthless killers.
