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Heart Rate Zones

Want to burn more calories or reach the limits of the body? Check out what those heart rate numbers mean on our wrist buddy!

Exercise intensity can be effectively gauged through heart rate zones. These zones are established as percentages of an individual’s maximum heart rate. Traditionally, a simple formula based on age (220 minus age) was used to estimate maximum heart rate.

However, for a more personalized understanding of exercise intensity, experts now favor the Karvonen formula. This method incorporates resting heart rate, providing a more precise picture of exertion levels.

Essentially, heart rate zones reflect how hard the heart labors to pump blood and meet the demands of physical activity. A higher heart rate zone indicates greater exertion by the body.

Five distinct heart rate zones exist, ranging from zone 1 to zone 5.

  • Zone 1
    In this zone, a significant portion (85%) of burned calories comes from fat. While overall calorie expenditure is lower compared to higher zones, activity in this zone can be sustained for extended periods. Conversation flows easily at this intensity.
  • Zone 2
    Here, approximately 65% of calories burned are derived from fat. Light conversation is still possible, although occasional pauses for breath might be necessary.
  • Zone 3
    Fat burning dips to around 45% in this zone. Conversation becomes noticeably more challenging.
  • Zone 4
    Fat is no longer the primary fuel source. Maintaining this intensity for more than 15 minutes is difficult. Speech is possible but highly discouraged due to exertion.
  • Zone 5
    This zone represents maximal effort, sustainable only for short bursts. Conversation is entirely out of the question.

Target heart rate by age

  • These are estimates and shouldn’t replace personalized recommendations from a healthcare professional.
  • The calculation for maximum heart rate is based on 220 minus the age (220 – Age = Estimated Maximum Heart Rate).
  • The corresponding range represents the target heart rate zone as a percentage of the estimated maximum heart rate.
  • The two zones represent different exercise intensities:
    • Moderate Intensity (50-70%)
    • Vigorous Intensity (70-85%)

Target Heart Rate Table

Age GroupTarget Heart Rate Zone (50-85%)Estimated Maximum Heart Rate
20s100-170 bpm200 bpm
30s95-162 bpm190 bpm
30s93-157 bpm185 bpm
40s90-153 bpm180 bpm
40s88-149 bpm175 bpm
50s85-145 bpm170 bpm
50s83-140 bpm165 bpm
60s80-136 bpm160 bpm
60s78-132 bpm155 bpm
70s+75-128 bpm150 bpm

Optimizing Workouts with Heart Rate Zone Training

Heart rate zone training provides a valuable tool for maximizing exercise benefits. These zones, expressed as percentages of maximum heart rate, offer insights into the body’s fuel utilization during workouts.

A traditional formula based on age can estimate maximum heart rate, but we can further tune our heart rate zones if we really like to. The Karvonen formula incorporates resting heart rate, leading to a more precise understanding of exertion levels.

Heart rate zones essentially reflect the intensity at which the heart works to pump blood and meet exercise demands. A higher zone indicates greater exertion.

ZoneDescriptionIntensity% Max Heart RatePrimary Fuel Source
1Warm-up, Recovery, EasyLow-Moderate50-60%Fat
2Aerobic, Endurance, Base, LightModerate60-70%Fat
3Tempo, Threshold, Cardio, ModerateModerate-High70-80%Fat, Carbs, Protein
4Lactate Threshold, Redline, HardHigh80-90%Carbs, Protein
5Anaerobic, VO2 Max, Peak, MaximumVery High90-100%Carbs, Protein

Is Heart Rate Tracking Essential?

While heart rate zone training offers valuable insights, the question remains: is it necessary for everyone?

For many exercisers, the body itself provides clear cues regarding workout intensity. Conversation fluency indicates a moderate-to-low heart rate zone. Conversely, struggling to maintain conversation suggests a higher zone.

Some of us finds heart rate zone data motivating. If such information keeps us engaged with our exercise program, that’s certainly beneficial. However, for others, the ‘talk test’ remains a perfectly adequate approach. The ability to converse comfortably during exercise signifies a moderate-intensity zone. Obsessing over numbers is counterproductive, especially if it hinders enjoyment of physical activity.

In essence, heart rate tracking serves as a valuable tool, but it shouldn’t become a barrier to achieving fitness goals.

Unlocking Personalized Training Intensity with Heart Rate Zones

For individuals seeking a data-driven approach to exercise, heart rate zone training offers a powerful tool. However, calculating these zones requires some mathematical exploration.

A widely used formula for determining training zones is the above already mentioned Karvonen formula. This formula incorporates an individual’s resting heart rate to create a more personalized approach:

Training Zone = ([Maximum Heart Rate – Resting Heart Rate] x % Intensity) + Resting Heart Rate

  1. Heart Rate Reserve
    This value is calculated by subtracting resting heart rate from maximum heart rate.
    (Maximum Heart Rate – Resting Heart Rate = Heart Rate Reserve)
  2. Training Zone
    The desired training zone intensity (expressed as a percentage) is multiplied by the heart rate reserve. This result is then added back to the resting heart rate to determine the specific training zone.
    (Heart Rate Reserve x % Intensity) + Resting Heart Rate = Training Zone)

1. Maximum Heart Rate

Understanding maximum heart rate (MHR) is essential for establishing safe and effective exercise parameters. MHR represents the highest number of beats per minute our heart can achieve during physical activity.

Two methods exist for determining MHR:

  1. Exercise Stress Test/VO2 Max Test
    Considered the most accurate approach, this test involves monitoring heart rate while performing strenuous exercise on a treadmill or bike. The heart rate reached at our peak exertion signifies our MHR.
  2. Estimated Calculation
    A simple formula (220 minus age) provides an estimated MHR. For instance, a 40-year-old would have an estimated MHR of 180 beats per minute (220 – 40 = 180).

It’s important to acknowledge that this formula may not be entirely accurate for everyone, as fitness levels vary significantly across individuals of the same age group. However, for those without a precise MHR obtained through testing, this calculation offers a valuable starting point for setting safe exercise thresholds.

2. Resting Heart Rate

Resting heart rate (RHR) stands in contrast to maximum heart rate, reflecting the heart’s beats per minute while at rest. Ideally, this measurement is taken in a seated or supine position. For most individuals, RHR falls within the range of 60 to 100 beats per minute. Generally, a lower RHR indicates a higher level of cardiovascular fitness.

Modern wearable technology allows for convenient monitoring of RHR throughout the day, often displaying an average over multiple days.

Alternatively, RHR can be determined manually by feeling the pulse at the wrist and counting beats over a one-minute timeframe. For optimal accuracy, Travers recommends performing this measurement first thing in the morning.

3. Heart Reserve

Heart rate reserve (HRR) is a valuable metric determined by subtracting resting heart rate (RHR) from maximum heart rate (MHR).


Consider a 40-year-old individual with a resting heart rate of 70 beats per minute (bpm). The estimated MHR for this person is 180 bpm (refer to previous section for MHR estimation).

HRR Calculation:

HRR = 180 bpm – 70 bpm
HRR = 110 bpm

In this scenario, the HRR is 110 bpm. This value serves as a personalized reference point for calculating heart rate training zones

4. Target Heart Rate Zones

Having established heart rate reserve (HRR), the next step is calculating target heart rate zones. These zones represent various exercise intensities and offer distinct training benefits.

Target Heart Rate Calculation

To arrive at target heart rate for a specific zone, multiply HRR by the percentage value corresponding to that zone and then add resting heart rate (RHR) to the product.

Target Heart Rate = (HRR x % Zone Intensity) + RHR

Zone Intensity Percentages

  • Zone 1: 50% (0.5)
  • Zone 2: 60% (0.6)
  • Zone 3: 70% (0.7)
  • Zone 4: 80% (0.8)
  • Zone 5: 90% (0.9)


Continuing with the 40-year-old individual whose HRR was calculated as 110 bpm (refer to previous section for HRR calculation) and assuming a resting heart rate of 70 bpm, let’s determine the target heart rate for zone 3:

  • Zone 3 Intensity: 70% (0.7)
  • Target Heart Rate for Zone 3 = (HRR x Zone 3 Intensity) + RHR
  • Target Heart Rate for Zone 3 = (110 bpm x 0.7) + 70 bpm
  • Target Heart Rate for Zone 3 = 77 bpm + 70 bpm
  • Target Heart Rate for Zone 3 = 147 bpm

By following this process for each zone, individualized target heart rate ranges for all five zones can be established.

Prioritizing Fat Burning Zones for Effective Weight Loss

Fuel Source and Heart Rate

As heart rate climbs through the zones, the body prioritizes different fuel sources to meet energy demands. At higher intensities (zones 4 and 5), carbohydrates and protein become the primary fuel source, while fat burning takes a backseat.

Zone Selection for Fat Loss

The body needs oxygen to oxidize fat and convert it to energy. The less oxygen it has the more it struggles to use fat as fuel and reaches out to other sources such as glycogen (carbs) and protein. This means that as long as we are in the zones 1 – 3 (50% to 70% of maximum heart rate) we are burning fat.

Short bursts of higher intensity training (zones 4 and 5) can be integrated for additional benefits, but these should not be the primary focus.

Muscle Mass and Metabolism

Strength training plays a vital role in weight loss beyond just calorie burning during workouts. Increased muscle mass elevates basal metabolic rate (BMR), the number of calories burned at rest. A higher BMR translates to more overall calorie expenditure throughout the day, further supporting weight loss efforts.

Optimizing Cardiovascular Health Through Exercise Intensity

The heart, like any other muscle, thrives on consistent activity to maintain strength. Exercise elevates heart rate above resting levels, promoting cardiovascular health.

Even modest increases in heart rate beyond resting levels contribute to cardiovascular health. These improvements include lower blood pressure, improved cholesterol levels, and better blood sugar regulation.

For optimal cardiovascular health, the American Heart Association recommends:

  • At least 150 minutes per week of moderate-intensity aerobic activity (corresponding to zones 1 to 3).
  • Alternatively, for those seeking time-efficient benefits, 75 minutes per week of vigorous aerobic activity (zones 3 to 4) can be pursued.
  • A combination of moderate and vigorous intensity exercise is also a viable option.

While heart rate monitoring can be a motivational tool, it shouldn’t become a barrier to exercise. Individuals who find heart rate calculations daunting can prioritize how their body feels during exercise.

Consulting a qualified healthcare professional, such as an exercise physiologist or physical therapist, allows for personalized recommendations regarding heart rate zones and their integration into an exercise program.


  • Targeted Exercise Benefits
    Heart rate zones, expressed as percentages of the maximum heart rate, allows us to tailor workouts towards specific goals, like fat burning or cardiovascular health improvement.
  • Effort Gauge
    Each heart rate zone reflects a distinct level of exertion the body is experiencing during exercise. This information helps us monitor and optimize our workout intensity.
  • Individualized Approach
    While heart rate zones offer a valuable framework, it’s important to acknowledge potential variations due to genetics or medications.
  • Maximize The Workouts
    By understanding and utilizing heart rate zones, we can elevate the workouts to a whole new level of effectiveness.

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