Question

Aerobic exercise is considered to be at an intensity of what percentage of maximum heart rate

Answer 1

Your heart rate rises during  aerobic exercise. It can rise from 70 beats per minutes (bpm) at rest to high as 170 bpm or even higher during exercise, depending on the intensity of the exercise' your fitness level, your age, and other factors.

Target heart rate zone range anywhere from 50% to 100% of your maximum heart rate (your maximum heart rate is based on your age). Aerobic  exercise is anywhere less than 85%. A nice starting point for a sedentary individual is somewhere in the range from 50% to 65% (you can always increase as you get more fit) and 65% to 85% for more conditioned individuals.