Exactly, I have done this many times. I have always noticed that when I become very tired, I will start laughing for no reason. (everything seems funny) My family knows me well enough to know what it means but other people in a group don't know what I'm even laughing at and will join in.
It is hysterical to watch happen. I have always thought that it was my own body's way of becoming more alkaline after overdoing some activity.