Alert not sending immediately

Content

Hi,

I have set up an exception on a report to alert me when a profile for staff accounts have been changed to a specific range of profiles. 

The alert is working in that it does alert me that a profile has been changed - but the report comes on the hour, every hour.  

When I set up the alert, I went into schedule and just put an email address and schedule in for the alert box, not for the top portion for days/times. 

Why is it sending it to me every hour, even when nothing has changed, and how can I get it to send to me immediately when the profile is changed and hits the exception?