Yes. Why you may asked?
Personally to me, it is that when you are happy, your body will react to it and function properly. Being happy means you will have no worries as it will not affect your body functions as people who are sad or not happy will indulge themselves with food, wine or alcohol, etc. This will be bad for their bodies and in a way, cut short their lives.
I have heard people in Japan who are living in a carefree lives, are living in their old ages.
Lastly, being happy and having no worries can make you free from sickness or diseases. So, let's be happy!