Used to emphasize the intensity of the hard work or effort put into a task. She sweated blood to start her own business.
Pro Tip 2/3
Not Literal
It's a figurative term, not actually sweating blood, but feeling like the work is that exhausting. Finishing this project on time meant we literally had to sweat blood.
Pro Tip 3/3
Achievement Focused
Often used when someone has worked exceptionally hard to achieve a specific goal. He sweated blood to earn that championship title.