Heart rate monitors can have various types of alarms. Many have an alarm to let you know when you are leaving your target heart rate. Alarms can be auditory, visual, and some can give a vibrating alarm.
If you want an alarm for leaving the target heart rate zone, be sure to read each product description carefully! Some have a "daily alarm" which is probably just to wake you up in the morning. Look to make sure it has the type of alarm you want.
$120.25
The Oregon Scientific Heart Rate Monitor Watch SE300 as an example has a heart rate alarm that can be set to beep or vibrate. The SmartHeart SE102 is an entry level heart monitor with a heart zone alarm that can be programmed for a visual or vibrating alert.
