The general equation for the normal individual is 220 - Age times the rated power (%) intensity. For instance, a 20-year old would figure their objective zone utilizing the above equation: 220-20=200. 200 x .60 = 120 and 200 x .80 = 160. Accordingly, this individual would keep their heart rate between 120 (low end) and 160 (top of the line) bpm.