The phrase ‘If you can’t take the heat’ indicates that if one is unable to cope with a stressful situation, then one should leave it to someone else who can handle it. The expression is also commonly used as ‘If you can’t stand the heat, get out of the kitchen’.
Example in use:
Sam: “I’m really stressed about all the cold calling I have to do for work.”
Mark: “Maybe you should find a different job. You know what they say: If you can’t stand the heat, get out of the kitchen.”
The phrase ‘If you can’t stand the heat, get out of the kitchen’ is widely attributed to Harry S. Truman, who used it already in 1942, while he was still a Senator. 'The Soda Springs Sun', a local newspaper in Idaho, quoted Truman this way: “Favorite rejoinder of Senator Harry S. Truman, when a member of his war contracts investigating committee objects to his strenuous pace: ‘If you don’t like the het, get out of the kitchen’.” In 1949, President Truman used another version of the phrase, a bit closer to the one we use today, to tell his staff not to be overly concerned about criticism related to their appointments: “I’ll stand by (you) but if you can’t take the heat, get out of the kitchen.”