State of the Excesive Applause

Disclaimer: this post will not actually discuss the content of the State fo the Union.

Why does everyone in the room during the State of the Union have to stand up and applaud the President after basically every sentence he says? DOES NOT MAKE SENSE! Standing up and sitting down every two seconds for this period of time could be considered a workout. Also if they waited till the end or half way through the speech the State of the Union would not take as long. All the applauding just seems unnecessary and extra.