What is the Aerobic Exercise Zone?

Heart Rate on Smartwatch
Heart Rate on Smartwatch. Guido Mieth/DigitalVision/Getty

The aerobic exercise zone is the intensity at which your body is using its aerobic metabolism system to produce energy from fat and glycogen. It spans the divide between moderate and vigorous intensity exercise. In general, you must use your major muscle groups continuously, especially the legs, to bring heart rate up into this zone. Aerobic activities include running, brisk walking, cycling, swimming, and rowing.

  • In systems that use five heart rate zones, the Aerobic Zone is zone 3, from 70-80% of your maximum heart rate. It is a heart rate where you can sustain exercise effort for a long period of time and get the benefits of improving your cardiovascular endurance.
  • A wider definition of the aerobic zone is from 40% to 85% of maximum heart rate. Within this wide range you are using aerobic metabolism during exercise and the body doesn't have to switch to anaerobic metabolism. For cardio exercise, you want to be within this wide zone.

What It Feels Like

To be considered aerobic, you are doing sustained major muscle group effort for 10 minutes or more. You are breathing harder than normal to take in the oxygen needed for aerobic metabolism, but you are not completely out of breath.

  • The aerobic zone is at the top of the moderate-intensity exercise zone (50% to 70% of maximum heart rate, which can be achieved with brisk walking.

Benefits of Exercising in It

This intensity zone is excellent for increasing the number and size of blood vessels in the muscles and improve lung ventilation. Your body is able to carry more oxygen to your muscles and take away waste products.

You also will be burning stored fat for fuel, which is desirable for those who want to reduce body fat and lose weight.

Heart Rates in the Aerobic Zone

In the five-zone definition, the aerobic zone is a heart rate between 70-80% of your maximum heart rate. It is a zone where you are exercising at moderate to vigorous intensity.  At 70-80% of your maximum heart rate, 50% of your calories burned in this zone are fats, 1% are proteins and 50% are carbohydrates.
Heart Rate Zone Calculator

Maximum heart rate varies by age, gender and athletic condition. For these maximum heart rates based only on age, these ranges would be in the aerobic zone if your resting heart rate is 60:

Aerobic Zone Heart Rates



Aerobic Zone BPM

25195136-156 bpm
30190133-152 bpm
35185129-148 bpm
40108125-144 bpm
45175122-140 bpm
50170118-136 bpm
55165115-132 bpm
60160112-128 bpm
65155108-124 bpm
70150105-120 bpm


You are able to exercise in this zone for a long period of time, first using glycogen for energy and then, after about 40 minutes, stored fat. Even people who have lean bodies have plenty of stored fat, unless they have been starving. This is why you can perform endurance exercise for long periods in the aerobic zone.

You can replenish carbohydrates while you are exercising in the aerobic zone to keep the supply available to your muscles.