Zone 2 Cardio | The Ultimate 2024 Guide (With Examples)

If you’re like most aspiring fitness enthusiasts, you initiate your daily cardio sessions without the faintest notion that you’re placing your body into one of five distinct fitness zones. Regardless as to the  effort level you choose to apply during your exercise regimen, your heart rate will ebb and flow to keep pace with the amount of energy you’re exerting.

As sophisticated as the concept of heart rate zones may sound, there should be a special place in your heart — pun absolutely intended — for the second of the five zones. Engaging in Zone 2 cardio is a practice that has been increasing over the past decade, and for good reason. Familiarizing yourself with Zone 2 training will go a long way toward preserving and enhancing your overall health. 

What is Zone 2 Cardio?

In the most straightforward sense, Zone 2 cardio is one of five exercise zones commonly referenced for the purpose of contextualizing the effects of cardio training. (1) (2) Zone 2  specifically refers to cardiovascular exercise that takes place within your body’s aerobic exercise zone. The effort required to achieve this level is usually classified as low-intensity training, through low-intensity exercises capable of being sustained for long periods of time.

In addition to its association with aerobic conditioning, Zone 2 training is also synonymous with fat burning. When exercise begins and energy production commences, your body cycles through stored adenosine triphosphate, then creatine phosphate, and then stored glucose in that order.  At that point, your body develops the need for more oxygen to sustain your effort.

Your body will transition through each fuel source very rapidly, and will then capitalize on your increased oxygen uptake and begin burning fat that has been preserved in your fat stores. This fat oxidation is maximized at a heart rate of about 54 percent, which is just shy of Zone 2, but not yet at a rate where the burning of calories is accelerated. (3) 

As such, Zone 2 becomes an ideal meeting place of fat oxidation and escalated calorie burning. Moreover, because Zone 2 training still prevents your workout from becoming anaerobic, it limits the production of lactic acid in your muscle cells, which is caused by burning carbs for energy. (4) This greatly minimizes the discomfort of your workout.

What are the Heart Rate Zones?

To properly conceptualize what a  Zone 2 fitness routine should feel like, it’s helpful to see where the aerobic heart rate level stacks up within the heart rate hierarchy, along with which energy systems are in use. Training in each of these heart rate zones can administer significant benefits to your body, even at the lowest intensity levels.

Zone 1

Zone 1 cardio is achieved through very light activity. How light? So light that the operations of your cardiovascular system probably aren’t even on your mind. All the same, your slow-paced activities will still be burning calories, and helping you create a caloric deficit.

Casually strolling through your neighborhood, or walking on your treadmill at a slow and steady pace are both examples of exercise that will elicit a Zone 1 response from your heart. This means you will be operating at  just over 50 percent of your max heart rate. (1)

Zone 2

You’ll know that you’re engaged in Zone 2 training activity when the effort level required  to achieve your pace of movement becomes the product of conscious thought, and your body is clearly in need of more oxygen. Although your discomfort level is low, you’ll still be fully aware that you are exercising, and your heart rate is elevated. 

At this point, your body will rely on your oxygenated blood in order to sustain its activity as you motor along at a steady pace. If you’re like most people, you’ll enter this beneficial heart rate zone while operating at 60 percent to 70 percent of your maximum heart rate.

Zone 3

Zone 3 cardio takes the principles from Zone 2 training and ups the ante. Whereas Zone 2 exercises will probably be easy for you to sustain for at least 45 minutes, if not far longer, Zone 3 training is more physically demanding. 

Zone 3 is  a frequent heart rate training zone for athletes attempting to stretch their performance potential and sustain a consistent output during periods of elevated discomfort. You will be cranking along at between 70 percent and 80 percent of your max heart rate while training in Zone 3.

Zone 4

If you’ve ever indulged in Zone 4 cardio, you know how difficult it can be. While you won’t quite be subjecting yourself to a series of all-out sprints, you will certainly be operating well within your body’s anaerobic training zone. 

As a result of the formidable nature of Zone 4 exercise, you should expect to be exhausted well before you reach the 10-minute mark of your training. This is because your muscle cells will be generating substantial lactic acid as you fly along at  80 to 90 percent of your maximum heart rate.

Zone 5

By the time you’re engaged in Zone 5 cardio, your fitness routine will almost certainly consist of segments of all-out sprinting, or exercises that produce an equivalent feel.  In most cases, a high intensity training routine built around Zone 5 will take the form of literal high intensity interval training in order to allow for ample recovery time in each session. No matter what your HIIT sessions consist of, every movement is meant to be performed at maximum intensity. 

As you might expect, your heart will respond to repeated rounds of high intensity exercise by beating right out of your chest. Also, due to how rapidly your energy level will be depleted, you won’t be able to train at the upper limit of your max heart rate for even 30 seconds without the quality of your output deteriorating noticeably.

The Benefits of Zone 2 Cardio

Part of the attraction of Zone 2 training is the wide range of health benefits you can achieve even during the low intensity workouts that will be prescribed to you. As expected, most of these improvements will be physical, but there are also some psychological advantages to indulging in Zone 2 training as well.

Fat Reduction

The fastest route to eliminating unnecessary body fat and losing weight is to implement a nutrition plan that hastens those outcomes. However, because of its ability to be maintained for extended periods of time, Zone 2 training is an excellent tool for burning calories and further contributing to a caloric deficit. 

As you maintain your aerobic activity in Zone 2, your body will continually burn calories by tapping into its fat deposits. This prompts your body to burn stored fat as fuel, thereby accelerating the precise weight loss you’re probably hoping for. (3)

Heart Health

Making frequent visits to the  aerobic heart rate zone can preserve and improve your mitochondrial function, which in turn enhances your cardiovascular health. This is unsurprising, as aerobic exercise has long been linked with reductions in all-cause mortality and cardiovascular disease. (5)

Because of the benefits Zone 2 exercise is known to convey to your heart, practitioners of sports medicine often prescribe aerobic training as a tool for heart preservation. This is also why the CDC recommends that you engage in 150 minutes of aerobic exercise each week. (6)

Aerobic Base Building

If you envy endurance athletes, and eventually hope to become an endurance athlete yourself, it can be exceedingly helpful to familiarize yourself  with cardio training within Zone 2. In fact, it’s common for runners covering moderate distances to average 20 miles of running each week as they prepare for competitions, with the majority of that time spent in the mid to upper portions of the Zone 2 range.

Not only can consistent aerobic training help you to maintain a trim figure through fat loss, but it can also improve your heart’s ability to ease itself into an elevated state, and for the rest of your body to sustain itself throughout extended competitions.

As you work towards your goals with Zone 2 training, remember that electrolyte hydration plays a pivotal role in fat metabolism and endurance.

Sustainable Training

The training style of Zone 2 cardio is more conducive to repeat performances than higher intensity sessions. This is because training routines that include low-impact cardio tend to be very easy to physically maintain over the long haul. 

One of the most important features of a training routine is its ability to be replicated. In keeping with this,  Zone 2 training provides a comfortable way to achieve health goals without discouraging future workouts through overly intense exercises that cause physical damage.

Metabolic Health

The harmful set of conditions that are collectively known as metabolic syndrome are a wide waistline, high blood pressure, high blood sugar,  high blood triglycerides, and low HDL cholesterol. Sustained Zone 2 exercise boosts metabolic health through fat oxidation, and consistently  burning glucose. (8)

In the process of disposing of stored glucose, Zone 2 training also boosts your insulin sensitivity. This is because the act of glucose disposal actually lowers insulin resistance. As a result, the more glucose you dispose of, the more your insulin sensitivity is increased. (8)

How to Determine Your Zone 2 Heart Rate

To quickly identify your Zone 2 heart rate, there is a quick mathematical procedure you should follow.  The method suggested by the American Heart Association requires that you first subtract your age from 220 to find your max heart rate. From there, multiply the resulting figure from 0.6 and 0.7 to determine the upper and lower boundaries of your Zone 2 heart rate. (9)

For example, if you are 30 years old, subtracting your age from 220 will leave you with a maximum heart rate of 190 beats per minute. Multiplying your max heart rate by 0.6 and 0.7 respectively will leave you with a range of 114 to 134 beats per minute. For all practical purposes, you will be engaged in Zone 2 training as long as your heart rate falls within this range.

However, if you’re in the middle of an easy jog and want to ensure that your exercise intensity is sufficient to burn fat, you can ascertain your effort based on perceived exertion through the talk test. If you are moving fast enough that it would be impossible  to comfortably maintain a long-term conversation, but you can still get a few sentences out without much difficulty, you’re probably operating within Zone 2.

Zone 2 Cardio Exercises and Workouts

Most aerobic fitness routines are rhythmic, low intensity workouts that sustain your heart rate within Zone 2 for their full duration. Because of this, there is a wide range of exercises and workout routines you can use to enter this safe, stable, and functional zone of cardio. Just remember to prevent your routine from becoming too light, or overly intense.

Studio Aerobics

Owing to the innovative mind of Jacki Sorenson,  studio aerobic routines display their intention prominently within their name. Originally marketed as “aerobic dance,” and eventually taking on several adjacent forms, aerobic workouts permit you to sustain your heart rate in an optimal zone for extended training sessions. 

This should serve as a tremendous encouragement to you, since the effectiveness of aerobics demonstrates how unnecessary equipment and open space are for achieving superlative health. Instead, you can safely achieve a satisfying workout in a relatively confined space.

Jogging

Initially devised as something of a walk-run hybrid, jogging permits you to rapidly elevate your heart rate into Zone 2 without placing your knees or other joints at much of a risk for an injury. As such, jogging is easily performed both outdoors and indoors, on open roads, high school tracks, or treadmills, and is a surefire way to build your aerobic base and tap into stored fat as a fuel source.

Beyond that, jogging serves as an efficient pathway between walking and running, and can assist you as you make the transition to more challenging forms of physical activity.

Swimming

If you would prefer to burn fat through Zone 2 training while completely eliminating the pull of gravity, look no further than swimming. Navigating your way through the water at a slow pace enables you to keep your body moving and your heart pumping while you traverse an environment that is relatively weightless.

With that being said, swimming will require you to have developed an additional skill that can be challenging to learn. However, if you possess the ability to swim, you are able to engage in a form of cardiovascular exercise that can also challenge the muscles of your body in ways that walking and running cannot. 

Elliptical Machine

If you’re certain that you would prefer to do your cardio indoors in a comfortable environment, an elliptical machine might be your preferred option. The movement of the foot pedals provides you with constant support, which makes it very easy to control the pace and intensity of your training session.

On top of being a low-impact, low-intensity form of exercise that minimizes the risk to your joints, elliptical training offers opportunities to train in air-conditioned settings while watching your favorite forms of video entertainment. This can help you to pass the time far more easily.

Integrating Zone 2 Training Into Your Workout Routine

Because Zone 2 workouts are intentionally designed to be as harmless  to your body as possible, this makes them exceedingly easy to insert into your existing training routines in different ways.

Extended Warm-Up and Cool Down

If you enjoy easing in and out of your resistance training sessions, or even your interval training routines, Zone 2 cardio can provide an optimal bookend to your training. This is because Zone 2 training efforts neatly overlap the exertions of  warm-up and cooldown sessions. 

Therefore, if you tack on 10 to 15 minutes of Zone 2 exercise as either a prelude or a postlude to your resistance training, you can boost your heart health, shed some additional calories, and chip away at the CDC’s recommendation for weekly cardiovascular exercise in the process.

Rest Day Activity

Assuming you subscribe to the theory that your days of intense training should have rest days inserted between them, Zone 2 cardio can enable you to remain active in a way that won’t interfere with your muscle recovery. 

Consequently, you can keep chipping away at your caloric deficit and remain active while your muscles are still able to fully replenish themselves. This can leave you with more energy, and prepare you for more intense exercise the following day.

Second Workout

Thanks to the benign nature of Zone 2 training — especially with respect to your joints and muscles — whatever you do during a training session will have minimal effects on your resistance training sessions. This also rings true if you want to challenge yourself through  more intense cardio sessions during other times of the day. (10)

With this being the case, if you prefer to train more than once each day, your morning flirtation with Zone 2 will not inhibit your capacity to hoist heavy weight  and build muscle mass in the evening. This means you can get the most out of your cardiovascular workout without worrying that it is stifling your strength gains.

Common Misconceptions and Mistakes

Just because Zone 2 cardio is an excellent tool for boosting fat loss, combating heart disease, and enhancing overall fitness, that doesn’t mean it’s a one-size-fits all health solution. While Zone 2 training will make your life better in several ways, there are a few ways its principles can be misapplied.

A Zone 2 Exercise Won’t Build Large Muscles

While training in the second of the five heart rate zones will boost the efficiency of your heart and help keep you trim, it won’t build your muscles. The very nature of Zone 2 training means that you’ll train slow-twitch muscle fibers, which are smaller than the fast-twitch fibers used for sprinting or heavy lifting. (11)

If you’re hoping to consistently enlarge your muscle fibers, you’ll need to find a way to train for hypertrophy. This requires you  to find a form of scalable resistance training that spurs your muscles to grow continuously. (12)

Zone 2’s Training Intensity Won’t Make You An Explosive Athlete

There’s no doubt that Zone 2 training can ease your body’s ability to operate with a moderately elevated heart rate for long periods of time. However, to be competitive against elite athletes  in most sports-oriented competitions, you’ll usually need to build muscles capable of delivering a top-tier athletic performance. 

To build a heart and body that can hold steady under that strain, you’ll need to spend time training with an all-out effort at the highest intensity levels. This doesn’t mean you should never train in Zone 2, but it does mean that Zone 2 won’t give you all of the abilities you’re looking for.

Zone 2 Is Not Just A Gateway To The Higher Zones

Because Zone 2 is only the second of five zones, you might be tempted to think of it as a novice heart rate zone in which you train slowly.  Therefore, you may view the other zones as more attractive. 

Realistically, whether or not Zone 2 cardio is ideal for you is dependent upon your goals. Quite frankly, if one of your foremost goals is to avoid injuries, Zone 2  training is a critical ingredient in the formula for avoiding wear and tear, and high intensity sessions may not be your thing.

Tools and Resources

If you’ve been persuaded to occupy Zone 2 for at least a few of weekly cardio training sessions, here are some tools and resources to help you maximize your success.

Heart Rate Monitor Watches

It’s one thing to estimate your heart rate by feel — which can be done quite literally if you manually check your pulse — but there are ways to get more precise measurements. One of those ways is to purchase one of the several watches and other wrist-worn devices that can be used to monitor your heart rate. This can be a valuable tool for ensuring you’re within the accepted parameters of  Zone 2. 

Move Phone Apps

If you’re not a huge fan of feeling your way through your cardio session, but you also don’t want to wear a device on your wrist throughout your training, there are smartphone apps that can help. If you download an app like InPulse, you can scan your heart rate and get a close estimate of your performance level at any time during your workout. This way, you can quickly assess whether or not you have maintained immersion in Zone 2 during training.

Your Body’s Zone Defense

There are plenty of ways to structure your workouts to yield favorable results in your life. However, if you want to prioritize weight loss and heart health while minimizing physical strain, Zone 2 cardio is among the most reliable methods to ensure that you’ll achieve those objectives, slowly, surely, and safely.

References and Further Reading

1. Moreno MR, Rodas KA, Bloodgood AM, Dawes JJ, Dulla JM, Orr RM, Lockie RG. The Influence of Aerobic Fitness on Heart Rate Responses of Custody Assistant Recruits during Circuit Training Sessions. Int J Environ Res Public Health. 2020 Nov 5;17(21):8177. doi: 10.3390/ijerph17218177. PMID: 33167476; PMCID: PMC7663998.

2. Rodas KA, Moreno MR, Bloodgood AM, Dawes JJ, Dulla JM, Orr RM, Lockie RG. The Effects Aerobic Fitness has on Heart Rate Responses for a Custody Assistant Recruit Class Performing a Formation Run. Int J Exerc Sci. 2021 Oct 1;14(4):1219-1233. PMID: 35096241; PMCID: PMC8758157.

3. Carey DG. Quantifying differences in the "fat burning" zone and the aerobic zone: implications for training. J Strength Cond Res. 2009 Oct;23(7):2090-5. doi: 10.1519/JSC.0b013e3181bac5c5. PMID: 19855335.

4. Rabinowitz JD, Enerbäck S. Lactate: the ugly duckling of energy metabolism. Nat Metab. 2020 Jul;2(7):566-571. doi: 10.1038/s42255-020-0243-4. Epub 2020 Jul 20. PMID: 32694798; PMCID: PMC7983055.

5. Nystoriak MA, Bhatnagar A. Cardiovascular Effects and Benefits of Exercise. Front Cardiovasc Med. 2018 Sep 28;5:135. doi: 10.3389/fcvm.2018.00135. PMID: 30324108; PMCID: PMC6172294.

6. How much physical activity do adults need? Centers for Disease Control and Prevention. Retrieved February 4, 2024. https://www.cdc.gov/physicalactivity/basics/adults/index.htm  

7. Fokkema T, van Damme AADN, Fornerod MWJ, de Vos RJ, Bierma-Zeinstra SMA, van Middelkoop M. Training for a (half-)marathon: Training volume and longest endurance run related to performance and running injuries. Scand J Med Sci Sports. 2020 Sep;30(9):1692-1704. doi: 10.1111/sms.13725. Epub 2020 Jun 3. PMID: 32421886; PMCID: PMC7496388.

8. Doctrow, Brian. Research in Context: Obesity and Metabolic Health. National Institutes of Health. October 17, 2023. Retrieved February 4, 2024. https://www.nih.gov/news-events/nih-research-matters/research-context-obesity-metabolic-health  

9. Target Heart Rate and Estimated Maximum Heart Rate. Centers for Disease Control and Prevention. Last Reviewed: June 3, 2022. Retrieved February 4, 2024. https://www.cdc.gov/physicalactivity/basics/measuring/heartrate.htm  

10. Schroeder EC, Franke WD, Sharp RL, Lee DC. Comparative effectiveness of aerobic, resistance, and combined training on cardiovascular disease risk factors: A randomized controlled trial. PLoS One. 2019 Jan 7;14(1):e0210292. doi: 10.1371/journal.pone.0210292. PMID: 30615666; PMCID: PMC6322789.

11. Plotkin DL, Roberts MD, Haun CT, Schoenfeld BJ. Muscle Fiber Type Transitions with Exercise Training: Shifting Perspectives. Sports (Basel). 2021 Sep 10;9(9):127. doi: 10.3390/sports9090127. PMID: 34564332; PMCID: PMC8473039.

12. Krzysztofik M, Wilk M, Wojdała G, Gołaś A. Maximizing Muscle Hypertrophy: A Systematic Review of Advanced Resistance Training Techniques and Methods. Int J Environ Res Public Health. 2019 Dec 4;16(24):4897. doi: 10.3390/ijerph16244897. PMID: 31817252; PMCID: PMC6950543.