really very curious question!! Laughing is great exercise for your lungs due to it helps the lungs into oxygen, and then exhale. it increase oxygen into the blood which travels throughout the body which flows healthy oxygen rich blood to all of our organs, and cells. it just makes you feel so darn good. If you were upset about something, and someone makes you laugh, you will forget for a moment what you were upset about. you can get many benefits from laughing like-- Improves your breathing Helps lower your blood pressure Helps you digest your food Improves your breathing Reduces Stress Releases endorphins Reduces depression Internal exercise (the belly) Relaxes your shoulders Makes you feel good

And you don't worry!

When you have a good mood, you're not sick! And your immunity is huge!