What does the phrase "can't take the heat" mean?

Can't tolerate the stress or effort or something about the job, or thing being described.

it means unable to stand the pressure, tension, or stress.

Don't persist with a task if the pressure of it is too much for you. The implication being that, if you can't cope, you should leave the work to someone who can.

http://www.phrases.org.uk/meanings/get-out-of-the-kitchen.html

https://www.usingenglish.com/reference/idioms/take+the+heat.html

if you can’t stand/take the heat

used for telling someone that they should not do something if they cannot deal with the difficult or unpleasant aspects of it

http://www.macmillandictionary.com/dictionary/british/if-you-can-t-stand-take-the-heat-get-out-of-the-kitchen

http://www.dictionary.com/browse/take-the-heat

It means that a person cannot take criticism--you know--like the current president.