Laughing decreases cortisol, the stress hormone

When you're stressed, cortisol constricts your blood vessels and reduces your blood circulation. Laughing can work as a natural anecdote. 

Keeps your 'good' cholesterol high

When you laugh, the good cholesterol flows and pushes the bad cholesterol back to the liver, keeping your heart safe and sound. It is then eliminated by the body.

Reduces inflammation in the arteries

When you burst into laughter, it triggers the inner lining of your blood vessels to release nitric oxide, a vital compound that reduces inflammation. 

Improves the functioning of your blood vessels

Laughter causes the inner lining of blood vessels called endothelium to rise and expand, causing an increase in blood flow.