When someone says they've sweated blood when they've worked hard you don't take them literally. Sometimes, however, people can actually sweat blood. A rare condition known as hematohidrosis can afflict people who are under intense mental or physical stress. The tiny blood capillaries around the sweat glands can rupture, causing blood to leak into the gland and get mixed in with the sweat that exudes from them. Even more! Crying blood is also possible!

More information:

medicalnewstoday.com/how-rare-is-hematidrosis