determining target heart rate

I know the formula .... 220-times age 5 through 7 This means 220-35 X .5 through 7 comes .... The problem is 92-129 my resting heart rate is 115 What rule can I use if my heart rate is normally fast?

Use the talk test - if you can not talk or just during your workout can talk after his heart rate is too high - you can talk words and phrases then you are the heart rate within the target - if you sing or whistle during his training after his heart rate is too low to be sure enough faster than you're actually trying and burning fat, but not too fast because you want to keep pace with all the training (without stopping or reducing)