grueling

grueling [ GROO-uh'-ling ]
[ noun, adjective ]

MEANING :
1. (adj.) physically and mentally tiring or exhausting
2. (n.) an exhausting experience

USAGE EXAMPLE 1 :
The children reached the top of the hill after a grueling climb.

USAGE EXAMPLE 2 :
She was rushed into surgery and after a grueling 10-hour operation, Kang is now recovering well and will be able to live a normal life.