how to find your target heart rate your target heart rate during moderate intensity activities should be about fifty percent to seventy percent of maximum heart rate. During vigorous physical activity it’s about seventy percent to eighty five percent of maximum. if your age if forty five years old your target zone is eighty eight to one hundred forty nine beats per minute abbreviated as b p m and your maximum heart rate is one hundred seventy five b p m at age 50 the target is eighty five to one hundred forty five b p m with a maximum of one hundred seventy at age fifty five the target is eighty three to one hundred forty b p m with a max of one hundred sixty five at age sixty the target is eighty to one hundred thirty six b p m with a max of one hundred sixty at age sixty five the target is seventy eight to one hundred thirty two b p m with a max of one hundred fifty five at age 70 the target is seventy five to one hundred twenty eight b p m with a max of one hundred fifty