How does socket.io respond to a long period of inactivity

I am having some issues with my application after a long period of inactivity. I am trying to figure out if socket.io simply stops emitting if no connection is made for a long period of time or if the problem is elsewhere. I would like to point out that the other components of the app work fine after the inactivity period (TCP connections) and my only issue thus far is with socket.io. Can anyone explain to me if the same principals that socket.io uses for client connections (heartbeat for example) is used on the server side aswell?