The phrase "sweat blood" means to work extremely hard and undergo a lot of physical or mental strain. There are several synonyms that can be used in place of this phrase, such as "toil," "labour," "struggle," "persevere," "grind," and "exert oneself." These words all convey the same message that a significant amount of effort is required to achieve a particular goal or outcome. Other related expressions include "bend over backward," "go the extra mile," "put in the work," and "give it your all." Whether in sports, academics, or career pursuits, the effort required to succeed is often significant, making these synonyms for "sweat blood" highly relevant and useful.