Ever wonder what a shiver is?
If your body temperature starts falling, one way to heat it up is to get your muscles moving, and if you won't do it by jumping or running, your body will kick-start them in a more desperate fashion.
Ever wonder what anxiety is?
If your life fails to inspire, one way to get things going is to go out and do something, and if you won't do it by embracing new risks, will kick-start it in a more desperate fashion.
Kick-start your life yourself, before your mind does it for you.