To find your training heart rate zone, you need to subtract your age from 220, then calculate 65% of this amount for the lower end of your training zone and 80% for the upper limit.

220 – age * .65 = lower limit
220 – age * .80 = upper limit

To find your pulse rate, you will need a watch with a second hand. There are several points at which the pulse can be felt easily: the neck on either side of the Adams apple; the writs. Apply light pressure to find the pulse. Taking your pulse for 10 seconds and multiplying it by 6 is an optimum way to measure whilst maintaining the intensity of training. It is best to take a measurement after each 10-15 minutes of exercise.