Enter your age below in the calculator to see the predicted heart rates for each of the 5 Training Zones:

These heart rate-based training zones should correlate well with other physiological variables of interest, e.g. blood lactate, breathing rate, and their various thresholds, though individuals and certain types of conditioning can vary.

Understanding Heart Rate Training Zones

The current exercise guidelines recommend that all adults complete some combination of at least 150 to 300 minutes of moderate and/or 75 to 150 minutes of vigorous intensity conditioning per week in addition to lifting weights twice a week to support health. [1] These recommendations define moderate and vigorous intensity conditioning as activities being 3 to 5.9 or greater than 6 metabolic equivalents (METs), respectively, where a MET refers to the amount of energy being used during the activity. While we agree that these are reasonable targets, the MET-based intensity recommendations leave much to be desired. In the sections below, we’ll discuss how-to use heart rate and training zones to get in both the right amount and right type of cardio. 

What Are Exercise Heart Rate Zones?

Intensity refers to how hard the body must work to perform the activity, e.g. the work rate, effort level, or metabolic challenge. In conditioning, intensity specifically refers to energy demand during exercise in conditioning, where higher intensity exercise requires more energy than lower intensity activities. 

Intensity for conditioning can be communicated a number of different ways, such as metabolic equivalents (METs), Rate of Perceived Exertion (RPE), percentage of maximum heart rate, and many more. Exercise intensity zones have been used by researchers, coaches, and athletic organizations as a way to correlate heart rate to other physiological variables, e.g. blood lactate levels, percentage of VO2max, and so on. 

There are a number of different models that have been popularized, namely the 3- and 5-zone models of conditioning exercise intensity, though there’s no consensus on which one is best. We’ll limit our discussion to only the 5-zone model for the rest of this article. 

In both models, each zone correlates to a specific range of heart rate range and training stress based on the zone’s unique physiological milieu.  For example, zone 1 represents an exercise intensity where little lactate is being generated, indicating a relatively low amount of anaerobic (without oxygen) metabolism. This type of exercise could be continued for hours. In contrast, zone 5 correlates to a much higher exercise intensity where so much lactate is being produced, the body cannot keep up with it. 

To summarize, heart rate zone represents a different exercise intensity, heart rate, and corresponding fitness adaptation. Training zones can be helpful for exercise prescription in order to target specific results without overdoing it. 

Predicted heart rates for exercise zones can vary significantly between individuals, different types of conditioning, different environments, and so on. Training zones based on heart rate should be sufficiently wide to result in most people achieving the desired physiological response to exercise, e.g. lactate level, respiratory rate, and so on, without having to directly test that variable. For this reason, we can also attach a Rating of Perceived Exertion (RPE) value to each zone. We acknowledge that training zones are a bit squishy without more objective data, but believe these ranges are reasonable, nonetheless. With that in mind, let’s dive deeper into how our calculator works!

How to Calculate Heart Rate Zones

The calculator we developed estimates a heart rate range for each zone based on an individual’s maximum heart rate. An individual’s maximal heart rate (HRmax) is the highest heart rate that someone can attain during an all-out physical effort. An individual’s HRmax can change due to a number of factors:

• Aging- Increasing age seems to reduce the heart’s intrinsic heart rate and maximal heart rate similarly, where the intrinsic heart rate is how quickly the heart would beat without any input from the autonomic nervous system. The heart may also be less responsive to the “fight or flight” response with age. [2]
• Training- Some have reported a decrease in HRmax with training, which seems counterintuitive, but is thought to be due to increased efficiency and coordination of the cardiovascular and nervous systems. [3]
• Exercise Type– Measured HRmax may also differ based on how it is tested, e.g. cycling tends to produce a 5 to 10% lower HRmax than running. [4]

Our calculator uses the Tanaka equation, e.g. HRmax= 208 – 0.7 (age), which tends to agree relatively well with direct measurements of HRmax. It is also similar to the Gellish and Arena equations, both of which perform similarly well against graded exercise tests of HRmax. [5] From there, the calculator uses the following percentages to denote the 5 training zones:

• Zone 1: 63 to 72% HRmax
• Zone 2: 72 to 79% HRmax*
• Zone 3: 79 to 85% HRmax
• Zone 4: 85 to 90% HRmax
• Zone 5: > 90% HRmax

Please note that these zones are a bit different than the graphic above. For this calculator, we wanted to narrow the HR zones slightly to make the targets a bit more actionable and accurate for producing the desired training intensity. Admittedly, these are estimates that will work well for many, but not for others. *Zone 2 is also intentionally a bit narrower and higher in an effort to get people near the “top” of the zone and really differentiate it from zone 1, as this seems to be useful for VO2max increase. [8]

For increased accuracy and precision, an individual could perform a 20-minute maximum exercise test on a bike, treadmill, rower, or other modality they are familiar with. During this test, the goal would be to go as hard as possible at a sustained pace for the full 20-minutes. The average HR during this test would represent a “threshold heart rate”, which could be translated into custom heart rates for the 5-zone model:

• Zone 1: 70-80% threshold heart rate
• Zone 2: 80 to 88% threshold heart rate
• Zone 3: 88 to 94% threshold heart rate
• Zone 4: 94 to 99% threshold heart rate
• Zone 5: > 99% threshold heart rate

Whether using the predicted zones based on a calculated HRmax or a tested threshold heart rate, these training zones and their associated RPEs can help dial in an individual’s training intensity in order to produce the desired training stress and subsequent fitness adaptations.

How to Measure Resting Heart Rate

Resting heart rate (RHR) or pulse is the frequency of heart beats per minute (bpm) while inactive and typically ranges between 50 and 90 bpm, varies throughout the day, and decreases overnight.  It is an important biomarker of both health and performance, with elevated resting heart rates above 70 beats/min correlating with an increased risk of disease, and highly trained endurance athletes regularly having a RHR in the 30’s and 40’s while they’re awake! [6,7] Genetics, medications, lifestyle habits, and fitness can all influence your resting heart rate, but in general, lower is better. 

Resting heart rate can be measured in a number of ways such as an electrocardiogram (ECG) or blood pressure cuff in the doctor’s office, a smart watch, or by hand. To measure your resting heart rate at home:

• While sitting quietly at rest, take your resting heart rate on the inside of your wrist on your thumb side 
• Using the other hand’s index and middle fingers held together, lightly press down and feel for the radial artery’s pulse
• Count the number of beats for a full 60-seconds to find your resting heart rate

If you can’t quite find your radial pulse, you may also use the same technique over the carotid artery in your neck, just in front of the thick neck muscle called the sternocleidomastoid.  If needed, you may repeat the process twice and calculate the average of both values to obtain your RHR. 

Which Heart Rate Zone is Best For Cardio?

Each training zone is correlated with a range of heart rates that track with the intensity and energy demand during exercise, where higher intensity exercise requires more energy than lower intensity activities. As a general rule, 

As far as how much of each zone needs to be done for health, the available scientific evidence does not indicate that one zone or particular exercise intensity is better than another if done for the same amount or volume of exercise. However, we can take some cues from endurance athletes to get a better sense of things.

By definition, endurance athletes are mainly concerned with improving performance in sport. One metric of cardiorespiratory fitness that is often focused on is VO2max, as it tends to track reasonably well with performance. A higher VO2max is also associated with improved health, making this sports science potentially interesting to those concerned with longevity.

 A number of studies have investigated the “training-intensity distribution” of endurance athletes and have come up with a generalizable finding that high-level endurance athletes tend to do about 80% of their training in zones 1 and zones 2, and 20% in the higher zones. [8] Additionally, the more successful athletes tend to spend the majority of the 80% near the top of zone 2, whereas less successful athletes spend more time in Zone 1.[9]  As athletes get closer to their event, the training-intensity distribution tends to change, becoming more specific to the the sport.

In summary, we recommend that individuals perform at least 150-minutes of cardio per week, with the majority (80%) of it being zone 2, and 20% of it being a bit higher than that. For those new to performing conditioning, we’d recommend starting conservatively, with more zone 1 than zone 2 work to start and gradually working up over time.

Which Exercise Zone is Best for Weight Loss?

Weight loss results from a sustained energy (Calorie) deficit and exercise does increase the amount of energy used daily. That said, exercise alone isn’t great for weight loss, as this is primarily determined by diet. In fact, exercise is most beneficial for preserving muscle mass, improving feelings of fullness after a meal, and a long list of weight-independent health benefits relating to nearly every organ system in the body. 

With regards to cardio, the available evidence suggests that all training intensities do about the same when it comes to weight loss. While High Intensity Interval Training (HIIT) is often portrayed as a time efficient option or superior choice for weight loss, it does not seem to produce more weight loss than moderate intensity or “steady state” conditioning exercise. [10]

For weight management, we recommend that individuals first and foremost work towards lifting weights at least two times a week, while also completing 150-minutes of conditioning per week, while being active on most days. From there, the bulk of weight loss is going to be up to an individual’s diet. Adding more cardio, more lifting, and so on can lead to some additional weight loss in the short-term, but the diet is going to be far more important to long-term success and maintenance of weight loss than simply doing more or harder exercise. 

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