what is an unhealthy heartrate to have when you are working out?

Answer 1

During periods of rest your heart rate (HR) should be around 80-100 beats per minute. Any faster, and its tachycardia. Any slower and its bradycardia. One does have to take into consideration though that athletes, or people who do a lot of physical training, normally have slower heart rates than normal, untrained people. During exercise your heart rate should not double your normal HR.

For example, if you have a HR of 100 during rest, then anything at 200 and above would be considered unhealthy.