She's at her best when 'the heat is on'. [=when she feels a lot of pressure; when she needs to finish something quickly]
She said things in 'the heat of the moment' [=when she was angry for a short period of time] that she later regretted.
The company has 'turned up the heat on' [=has put extra pressure on] its employees to finish the job quickly.
(..) The second one's called "The Amazon Squad." Lady cops. Running characters include a crusty but benign police lieutenant... who's always getting heat from the commissioner... a tough, hard-drinking detective who thinks women belong in the kitchen... and a brilliant, beautiful young cop (..)1976 Network