How do you calculate your heart rate training zone?

Depends on what you are trying to do. If you want to work at peak range, it's 220 minus your age. So, if you're 22 years old, your peak heart rate is 198. Generally, you want to train at 60% to 80% of your peak. So, again, if you are 22, that would mean you should be at a heart rate of 118 on light days and 159 on hard days.