A good target heart rate range for a 26-year-old female, at 70-85 percent of a maximum heart rate, is 136 to 165. The target heart rate of a 26-year-old female is calculated based on maximum heart rate. Fitness level, age and physical condition contribute to the desired range, notes Healthline.
Mayo Clinic explains how to determine a target heart rate of 70 to 85 percent of a maximum heart rate, by using the following calculations:
Subtract the age, 26, from 220, which equals 194. The maximum heart rate is 194. Then multiply it by .7 to reach the lower end heart rate, which is 136. Multiply it by .85 to reach the high end heart rate, which is 165.