Zone 2 Cardio: What it is and How to Do it
by Ezra •7 minutes read
Last updated: 17 Jul, 2023
Zone 2 Cardio, also known as Zone 2 Heart Rate Training, involves working out at a moderate intensity level where your heart rate remains at 60-70% of your maximum heart rate. This form of low intensity exercise focuses on developing aerobic fitness and endurance.
Heart rate training zones are a valuable tool for endurance athletes who are seeking to optimise their workouts and achieve specific fitness goals. A heart rate training zone is a way to describe and measure the intensity the body uses its aerobic metabolism system to create energy from glycogen and fat.
The 5 heart rate training zones, based on maximum heart rate (MHR)
Heart Rate Training Zone 1 - Recovery
Heart Rate Training Zone 1 is around 50-60% of your MHR. It is a very light intensity zone that is used for warming up and cooling down. This zone promotes blood circulation and aids in recovery.
Heart Rate Training Zone 2 - Aerobic Zone
Heart Rate Training Zone 2 is approximately 60-70% of your MHR. It is a moderate intensity zone, where your body primarily relies on aerobic metabolism. This zone improves aerobic endurance, burns fat, and helps build a strong cardiovascular base.
Heart Rate Training Zone 3 - Tempo Zone
Heart Rate Training Zone 3 falls within the range of 70-80% of your MHR. It is a moderately high intensity zone that pushes your aerobic capacity. This zone increases cardiovascular efficiency, improves lactate threshold, and develops sustainable speed.
Heart Rate Training Zone 4 - Threshold Zone
Heart Rate Training Zone 4 is around 80-90% of your MHR. It is a high-intensity zone where you are working close to your anaerobic threshold. This zone improves your ability to sustain high-intensity efforts, enhances lactate clearance, and increases overall speed and endurance.
Heart Rate Training Zone 5 - Anaerobic Zone
Heart Rate Training Zone 5 is approximately 90-100% of your MHR. It represents the highest intensity zone where you are working at or near your maximum effort. This zone is challenging and mainly focuses on improving your speed, power, and anaerobic capacity.
Zone 2 Cardio - What is it?
Zone 2 Heart Rate Training emphasises the importance of training in the aerobic zone to improve cardiovascular capacity, enhance fat metabolism, and build a solid foundation for overall fitness.
Zone 2 Cardio, also known as the ‘fat-burning zone’, primarily targets fat metabolism for energy during exercise. When exercising in Heart Rate Training Zone 2, a process called aerobic metabolism occurs which creates ATP (Adenosine Triphosphate). ATP is a small energy molecule that has various functions including moving our muscles. Our muscles need a steady supply of ATP to keep working. Aerobic metabolism provides our muscles with energy by relying on oxygen and using fuel sources like carbohydrates (stored as glycogen) and fats. During Zone 2 cardio training, your body will primarily rely on fat as an energy source and preserve glycogen stores.
The key benefits of Zone 2 training are an increase in cardiorespiratory endurance, improvement in recovery time, enhancement in VO2 max, reduced stress on the body, and a lowered resting heart rate. This is because as our bodies become better at using oxygen efficiently to make ATP, our aerobic capacity is improved. Exercising in this zone is also helpful for weight management as the body learns to use stored body fat for fuel rather than carbohydrates.
While Zone 2 Cardio primarily targets fat metabolism, it is important to remember that overall calorie burn is lower during aerobic exercises compared to high-intensity, anaerobic workouts like weightlifting or high-intensity interval training (HIIT). Always consult with a healthcare professional or fitness expert to determine the most suitable training approach for you.
How to do Zone 2 Cardio training
Examples of exercises that can be performed for Zone 2 Cardio training include easy jogging, brisk walking, cycling at a moderate pace, and swimming at a comfortable speed. These exercises predominantly rely on the aerobic energy system and can be sustained at 60-70% of your MHR.
The most popular way to calculate your maximum heart rate is the Maffetone Method.
Maffetone Method
Dr. Philip Maffetone, a renowned endurance and sports medicine coach, developed a training approach called the Maffetone Method. It is commonly used by elite athletes as it focuses on developing aerobic fitness and optimising fat metabolism, however it can be used by anybody wanting to improve their overall health and athletic performance.
The key principle of the Maffetone Method is to train within your individual aerobic threshold. Using the Maffetone formula, you will be able to calculate your Maximum Aerobic Function (MAF). The MAF provides you with a max heart rate for Zone 2 Cardio training, calculated by subtracting your age from 180. This number will be 60-70% of your MHR. Additional numbers may be subtracted from your zone 2 heart rate depending on certain factors.
To calculate your MAF:
Subtract your age from 180. For example, a 30 year old will have an upper limit of 150 MAF.
Subtract an additional 10 from this number if you have a major illness or are recovering from one, such as heart disease.
Subtract an additional 5 if your waist measurement is more than half of your height.
Subtract an additional 5 if you are injured, have allergies or asthma, or have regressed in training (including if you are only just getting back into it).
Do not change the number if you have been training at least four times a week without any of the aforementioned problems.
Add 5 if you have been actively training for over two years and have progressed in competitions without injuries.
Zone 2 Cardio workout - Running
Running is a popular form of Zone 2 Cardio. The workout would begin by briskly walking or lightly jogging for 5 to 10 minutes as a warm-up before running at a comfortable pace for 20 to 30 minutes, all the while ensuring that your heart rate stays within your predetermined Zone 2 range. Cool down with a slow walk or jog for 5 to 10 minutes. Aim to do this exercise at least 3 to 5 times a week.
Whilst working out, focus on maintaining a steady, controlled pace and concentrate on your heart rate. If necessary, make adjustments to your speed or effort level so that you can keep your MAF within Zone 2. You can use a heart rate monitor or wearable fitness tracker to keep track of your heart rate. Aim to run continuously without walking breaks, however do take short walking breaks if needed to keep your heart rate within the desired range.
Depending on your fitness level and goals, alter the duration of the run to suit your preferences and needs. A beginner is likely to start with 20 to 30 minutes of continuous exercise and gradually increase to 45 to 60 minutes as their fitness improves. Maintaining consistency allows your aerobic system to adapt and improve without pushing into higher intensity zones.
Talk Test
The Talk Test is a simple way to determine whether your heart rate is remaining within the Zone 2 Cardio training range. It is based on your ability to comfortably hold a conversation whilst exercising, meaning you should be able to speak in full sentences without excessive breathlessness. The Talk Test can be used in place of a heart rate monitor or wearable fitness tracker.
While exercising, try to have a conversation with a workout partner or speak out loud to yourself. Choose a topic that requires more than one-word responses, paying attention to your breathing and the ease with which you can talk.
If you find it challenging to speak in full sentences or feel excessively breathless while trying to converse, you may be working at a higher intensity beyond Zone 2. In that case, you can adjust your effort level to slow down and bring your cardiac output back down.
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