Whether you're an endurance athlete or a beginner starting your fitness journey, you've probably heard about zone 2 cardio. But why is it trending, and more importantly, should you be doing it?
Zone 2 cardio is a low-intensity, steady-state workout that allows you to sustain effort for an extended period while primarily using fat as fuel, says Gene Schafer, a NATABOC-certified athletic trainer and NSCA-certified strength and conditioning specialist. It involves exercising at 60-70% of your maximum heart rate and can be effective for losing fat, building endurance and improving heart health.
Lately, zone 2 cardio has gained popularity as more people focus on a long-term and sustainable approach to fitness rather than chasing fast results. Keep reading to see if you should add zone 2 cardio to your fitness routine.
What are heart rate zones?
"Heart rate zones are ranges of an individual's heart rate that suggest what energy course the body is using for fuel as they exercise. It's also a measure of intensity for how hard someone is exerting themselves during a workout, usually a focus of cardiorespiratory training," says Erin Mahoney, general manager of the National Federation of Personal Trainers and a personal trainer with more than 20 years of experience.
There are primarily five heart zones, from zone 1 to zone 5. Each has different intensity levels and energy sources. Here's a breakdown of each zone:
Zone | Maximum heart rate percentage | Exercise intensity level | Source of energy |
Zone 1 | 50 to 60% | Low | Fat |
Zone 2 | 60 to 70% | Moderate | Fat |
Zone 3 | 70 to 80% | Moderate to high | Fat, carbohydrate, protein |
Zone 4 | 80 to 90% | High | Carbohydrate, protein |
Zone 5 | 90 to 100% | Very high | Carbohydrate, protein |
Before calculating the exact heart rate needed for each zone, you first need to determine your maximum heart rate (MHR). You can calculate your maximum heart rate with the formula: 220 - your age.
Once you know your MHR, you can now calculate your heart rate zone using the Karvonen formula, which is:
([Maximum heart rate – resting heart rate] x percentage intensity) + resting heart rate = the heart rate needed for your zone
Resting heart rate is the number of times your heart beats while you're sitting still or lying down. As for percentage intensity, you'll want to go with the lowest percentage per zone. Then, turn that percentage into a decimal. For instance, zone 2 is 60% on the low end, which is 0.6.
This formula helps you exercise at the right intensity based on your goals, whether it's fat loss or endurance building.
If you have an Apple Watch, you can also enable the device to display your heart rate zone for you.
What is zone 2 cardio?
"Zone 2 is exercise that is performed at 60 to 70% of your maximum heart rate. It's a low-intensity, steady-state workout that allows you to sustain effort for an extended period of time while primarily using fat as fuel. It should feel comfortable enough to hold a conversation but still challenging," says Schafer.
"Another benefit is the activation of the cell's mitochondria. Zone 2 training is effective for improving mitochondria function as well as increasing the number of mitochondria in the cells. This is why zone 2 training has become so popular, especially when discussing longevity. The health of the mitochondria will have a direct impact on the effects of aging on the body," says Mike Deibler, an NSCA-certified strength and conditioning specialist and a certified personal trainer with the National Association of Sports Medicine and the American Council on Exercise.
Two examples of zone 2 cardio are:
Jogging: It's a slower running pace, mostly less than 6 miles per hour. It can improve your heart health and boost your mood without putting you at risk of injury.
Cycling: Cycling is a low-impact exercise that helps strengthen your lower body without putting a lot of stress on your joints. It can improve your mood and reduce the risk of heart disease.
Zone 2 cardio is generally quite safe. "Zone 2 is relatively easy to do with less impact on the body. It is not as stressful as higher intensity training, so we can recover much quicker from it and do it often," says Deibler.
Zone 2 cardio benefits
Zone 2 training is ideal for increasing stamina and endurance and will help you build an aerobic base, says Rachel MacPherson, an American Council on Exercise-certified personal trainer.
In reality, everyone would benefit from this specific type of training. It's particularly popular with endurance athletes and those seeking healthy aging benefits. But the reality is everyone would benefit from regular zone 2 training, says Deibler.
A few common benefits include:
- Low impact: Most zone 2 workouts are low impact and put less stress on joints, helping mitigate the risk of injuries. It's also not too taxing on the body, so it helps you stay active without demanding too much in terms of recovery, says MacPherson.
- Improves heart health: Zone 2 cardio can improve the strength of your heart and heart health.
- Energy efficient: Zone 2 cardio primarily uses fat as a source of energy, which may help to lower your body fat levels and support weight management.
- Easy to perform: It's quite easy for you to hit zone 2 cardio through activities you enjoy, such as jogging, cycling and even dancing.
- Faster recovery: You can recover faster from zone 2 cardio since it puts less stress on the body than high-intensity training.
Zone 2 cardio cons
Although zone 2 cardio has several benefits, it may also have a few downsides. These include:
- More time: It's time consuming because it takes about 45 minutes to be effective and it's really not ideal for strength training, says Schafer. Plus, exercising for such a long duration may be boring for some people.
- Slower calorie burn: If you're looking for body composition improvements, like losing weight, it's not extremely time efficient. According to Mahoney, you could burn more calories in a shorter period by transitioning into higher intensity intervals.
- No impact on anaerobic capacity: It won't improve your maximal oxygen consumption (VO2 max) or tap into your anaerobic energy system to build your anaerobic capacity, power, or speed like zones 4 and 5 will, says MacPherson.
- Little endurance improvement: If you're hoping to improve your overall stamina and speed over a distance or time, zone 2 cardio doesn't increase your endurance quite as much as working in zone 3 will.
Who is zone 2 cardio best for?
Zone 2 cardio is good for most people, but especially those who want to do cardio in recreational and more enjoyable ways than something like burpees or an intense indoor cycling session, for example, says Mahoney.
"People of all fitness levels and abilities can do some zone 2 cardio since the zones can be tailored to your individual max heart rate," says MacPherson. "Runners can use zone 2 cardio for the bulk of their training. Weightlifters, athletes and other active people can use zone 2 cardio as a way to boost physical activity, increase blood flow, regulate blood sugar and burn calories without interfering with their main sport or activity."
Zone 2 cardio tips
"I recommend using a heart rate monitor first, which can estimate your personal zone 2 heart rate over time, since everyone's resting and max heart rate will be different. Using a personalized number is ideal if you want the most accurate training guidance," says MacPherson.
You can also take the "talk test" if you're unable to monitor your heart rate. As per this test, while performing zone 2 cardio, you'll be able to talk comfortably, speaking around three to five words at a time before needing a breath. However, you won't be able to sing; being able to sing suggests you're not in zone 2 cardio.
Next, you may pick any activity, such as jogging, cycling, swimming or dancing. You can perform the activity for 30-45 minutes and build up from there. You should aim to perform the activity three to four times a week.
One final tip is to do your cardio on separate days from your weight lifting. Suppose you like to do both on the same day. In that case, it might be best to do your zone 2 cardio before you lift, especially on leg day (if your cardio includes running/cycling or other lower body work), so you don't overwork your muscles and impede post-workout recovery, says MacPherson.
Should the average person track their heart rate zone?
Tracking your heart rate during exercise is highly advised. It allows you to ensure you're not only hitting your target during exercise but also, during interval training, recovering appropriately before increasing intensity again, Mahoney explains.
It's also a helpful mechanism to gauge if you're overtraining or need recovery days. She adds that you might need some days off if you're having difficulty recovering out of a zone or pushing yourself into a specific zone.
However, Deibler says, "If you are newer to training or just getting back into it, I would first work on developing a regular habit of exercise before worrying about using heart rate zones. After months of consistent training, it might be something you can implement to help continue to see progress in your training."
The bottom line
Zone 2 cardio is an effective and sustainable way to lose weight, build endurance and improve your heart health without burning yourself out. You can choose various activities such as jogging, cycling, swimming or dancing as part of your zone 2 workout. Moreover, it's quite easy to perform, and recovery is faster compared to high-intensity exercises. However, it may feel slow, time-consuming and boring. Therefore, we sure to choose an activity you love to make zone 2 cardio enjoyable and a long-term part of your fitness routine.
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