Prevent Session cookie expiration being updated

I'm developing a Laravel 4.2 application where I poll the server frequently to update a list (every 5 sec). The problem is this is affecting the session expiration. I want the session to expire if the user is inactive but I don't want this polling to be considered as user activity. Now I'm looking at adding a filter to the route being polled but I'm after some advice on how to implement this filter. I want to prevent the session expiration from being updated. Any tips would be greatly appreciated..