The first rule of Zombieland; cardio. HIIT, high intensity interval timer, is a no frills timer for interval training routines, or anything you may need an interval timer for really. You may specify a number of seconds for each active period, a number of seconds for each rest period and, optionally, a number of seconds before the end of each rest period to warn of the upcoming active period giving you time to prepare. <ul> <li>No ads</li> <li>No trackers</li> <li>No permissions</li> <li>Ultra simple interface</li> </ul>