How to Calculate Your Target Heart Rate Zone

Your heart rate during exercise tells you whether you are working hard enough to improve fitness or pushing into territory that risks overtraining and injury. Learning to calculate and use your target heart rate zone transforms guesswork into precise, productive training. Whether your goal is fat loss, endurance building, or peak athletic performance, heart rate-based training puts you in control of every workout.

This guide walks you through the major heart rate formulas, breaks down the five recognized training zones, and provides real-world examples so you can start training smarter today.

What Is Target Heart Rate?

Target heart rate is the ideal range of heartbeats per minute during physical activity that allows you to exercise at a specific intensity level. It is expressed as a percentage of your maximum heart rate, the highest number of beats your heart can achieve per minute during all-out effort. The American Heart Association recommends exercising at 50% to 85% of your maximum heart rate for cardiovascular benefits.

Exercising below your target zone may not challenge your cardiovascular system enough to produce meaningful adaptations. Training above it for extended periods increases the risk of overtraining, excessive fatigue, and injury. Staying within your target zone ensures that each workout delivers the intended benefit, whether that is building an aerobic base, improving lactate threshold, or developing peak speed.

Maximum Heart Rate Formulas

Before you can find your target zone, you need to estimate your maximum heart rate. Two formulas are widely used, and each has strengths depending on your age and fitness background.

The Standard Formula (220 Minus Age)

The most commonly cited formula subtracts your age from 220:

A 30-year-old gets an estimated maximum heart rate of 190 bpm. A 50-year-old gets 170 bpm. This formula is easy to remember and widely used on gym equipment and in fitness apps. However, research shows it tends to overestimate max heart rate in younger adults and underestimate it in older adults, with a standard deviation of about 10 to 12 bpm.

The Tanaka Formula

Published in 2001, the Tanaka formula was derived from a meta-analysis of 351 studies involving 18,712 subjects:

For a 30-year-old, Tanaka gives 208 minus 21, equaling 187 bpm. For a 50-year-old, it gives 208 minus 35, equaling 173 bpm. The Tanaka formula is considered more accurate across age groups, particularly for adults over 40, because it was validated against a much larger and more diverse dataset than the original 220-minus-age formula.

The two formulas converge around age 40 and diverge increasingly for younger and older adults. If you are over 40, the Tanaka formula likely gives you a more realistic maximum heart rate estimate.

The Karvonen Formula (Heart Rate Reserve)

The Karvonen formula improves on basic percentage-of-max calculations by incorporating your resting heart rate. This matters because your resting heart rate reflects your current cardiovascular fitness. A highly fit person with a resting heart rate of 52 bpm and a sedentary person with a resting rate of 78 bpm should not train at identical heart rates, even if they are the same age.

The term (Max HR minus Resting HR) is called your Heart Rate Reserve (HRR). Multiplying HRR by an intensity percentage and adding your resting heart rate back produces a target that more accurately reflects effort relative to your personal fitness baseline.

Step-by-Step Karvonen Calculation

Here is how a 35-year-old with a resting heart rate of 65 bpm would calculate a 70% intensity target:

1. Estimate maximum heart rate: 220 minus 35 = 185 bpm
2. Calculate heart rate reserve: 185 minus 65 = 120 bpm
3. Multiply by intensity: 120 times 0.70 = 84 bpm
4. Add resting heart rate: 84 plus 65 = 149 bpm

This person's 70% Karvonen target is 149 bpm. Using the simpler percentage-of-max method, 70% of 185 equals 130 bpm, a substantially lower target that would not reflect the same relative effort.

The Five Heart Rate Training Zones

Exercise scientists divide heart rate intensity into five zones, each producing different physiological adaptations. Understanding these zones helps you structure your weekly training to match your goals.

Heart Rate Zone Chart

Most recreational exercisers benefit from spending 80% of their training time in Zones 1 through 3 and 20% in Zones 4 and 5. This 80/20 distribution, known as polarized training, is supported by research showing it produces better endurance gains than training exclusively at moderate intensity.

Practical Examples

Example 1: Beginner Walker Starting a Fitness Program

Carmen is 52 years old with a resting heart rate of 74 bpm. She has been sedentary for several years and wants to start a walking program to improve her cardiovascular health.

• Maximum heart rate (Tanaka): 208 minus (0.7 times 52) = 172 bpm
• Heart rate reserve: 172 minus 74 = 98 bpm
• Zone 2 target (60% to 70% Karvonen): (98 times 0.60) plus 74 to (98 times 0.70) plus 74 = 133 to 143 bpm

Carmen should aim for 133 to 143 bpm during her walks. If she checks her pulse and finds she is at 120 bpm, she needs to pick up the pace. If she hits 155 bpm, she is working too hard for her current fitness level and should slow down. Starting in Zone 2 for 30 minutes, three to four days per week, builds a solid aerobic foundation while keeping the exercise sustainable and enjoyable.

Example 2: Intermediate Runner Training for a 10K

Derek is 38 years old with a resting heart rate of 58 bpm. He has been running for two years and wants to improve his 10K race time.

• Maximum heart rate (Tanaka): 208 minus (0.7 times 38) = 181 bpm
• Heart rate reserve: 181 minus 58 = 123 bpm
• Zone 3 (easy runs, 70%): (123 times 0.70) plus 58 = 144 bpm
• Zone 4 (tempo runs, 85%): (123 times 0.85) plus 58 = 163 bpm

Derek structures his training week with three easy runs at around 144 bpm, one tempo run at 163 bpm, and one interval session alternating between 170 bpm (Zone 4/5) and 130 bpm (recovery). This approach builds endurance through volume while developing speed through targeted intensity. His heart rate monitor helps him avoid the common mistake of running easy days too fast, which leads to chronic fatigue and slower race times.

Example 3: HIIT Athlete Maximizing Performance

Priya is 28 years old with a resting heart rate of 52 bpm. She does high-intensity interval training four days per week and wants to optimize her work-to-rest ratios.

• Maximum heart rate (Tanaka): 208 minus (0.7 times 28) = 188 bpm
• Heart rate reserve: 188 minus 52 = 136 bpm
• Zone 5 work intervals (90%): (136 times 0.90) plus 52 = 174 bpm
• Recovery target (60%): (136 times 0.60) plus 52 = 134 bpm

Priya uses her heart rate monitor to ensure she reaches at least 174 bpm during work intervals and recovers down to 134 bpm before starting the next interval. Rather than using a fixed rest timer, she rests until her heart rate drops to her recovery target. This heart rate-guided approach ensures adequate recovery between intervals and prevents the diminishing returns that come from starting the next set before the cardiovascular system is ready.

How to Measure Your Heart Rate

You can measure your heart rate using three primary methods, each with different levels of accuracy and convenience.

Manual pulse check: Place your index and middle fingers on the side of your neck (carotid artery) or the inside of your wrist (radial artery). Count the beats for 15 seconds and multiply by four. This method is free and always available, but it requires stopping exercise momentarily, and the count can be imprecise during high-intensity activity when your heart rate is changing rapidly.

Chest strap heart rate monitor: A strap worn around the chest uses electrical sensors to detect each heartbeat. Chest straps are accurate within 1 to 2 bpm of medical-grade equipment and provide real-time data to a paired watch or phone app. They are the gold standard for exercise heart rate monitoring and are preferred by serious runners, cyclists, and athletes.

Wrist-based optical monitor: Smartwatches and fitness trackers use LED lights to detect blood flow changes in the wrist capillaries. They are convenient because you wear them all day, and they automatically track resting heart rate, exercise heart rate, and recovery. Accuracy is good during steady-state cardio but can drift during high-intensity or wrist-heavy activities. For general fitness tracking, wrist monitors provide sufficient accuracy for most people.

To measure your resting heart rate accurately, check it first thing in the morning before getting out of bed, on three consecutive mornings, and average the results. This gives you the most reliable baseline for Karvonen formula calculations.

Tips for Heart Rate-Based Training

Measure resting heart rate consistently. Take your resting heart rate at the same time each morning, lying still for at least one minute before counting. As your fitness improves over weeks and months, your resting heart rate will gradually decrease, and you should update your Karvonen calculations accordingly.

Account for cardiac drift. During prolonged exercise lasting more than 30 minutes, your heart rate naturally increases even if your pace stays the same. This phenomenon, called cardiac drift, is caused by rising body temperature and fluid loss. Do not chase a fixed heart rate number for the entire workout. Allow a 5 to 10 bpm drift upward during long sessions and focus on maintaining perceived effort rather than a rigid heart rate target.

Use the talk test as a backup. If your heart rate monitor fails or you forget it, the talk test provides a reliable intensity gauge. During moderate exercise (Zones 2 to 3), you should be able to speak in full sentences but not sing. During vigorous exercise (Zone 4), you can only say a few words before needing a breath. If you cannot speak at all, you are at or near maximum effort (Zone 5).

Reassess every 8 to 12 weeks. As your cardiovascular fitness improves, your heart becomes more efficient and your resting heart rate drops. Recalculate your training zones periodically so your targets continue to reflect your current fitness level. Failing to update zones means you may be training below your optimal intensity as you get fitter.

Common Mistakes to Avoid

• Ignoring resting heart rate in calculations. Using the simple percentage-of-max method instead of the Karvonen formula produces less accurate zones, especially for very fit or very unfit individuals. The extra step of measuring resting heart rate and using heart rate reserve is worth the effort.
• Obsessing over exact numbers. Heart rate formulas provide estimates with a margin of error of 10 to 12 bpm. Treating a calculated max of 185 bpm as absolute truth can lead to undertrained or overtrained sessions. Use formulas as starting points and adjust based on how you feel.
• Training in Zone 3 all the time. Many recreational exercisers default to a moderately hard effort every workout, never going easy enough to recover or hard enough to improve speed. This "gray zone" training produces mediocre results. Deliberately train easy on easy days and hard on hard days.
• Skipping warm-up. Jumping straight into your target zone without a 5 to 10 minute warm-up in Zone 1 stresses the cardiovascular system and increases injury risk. Always ramp up gradually.
• Using heart rate zones while on beta-blockers. Beta-blockers artificially lower heart rate by 20 to 30 bpm, making standard formulas inaccurate. If you take medication that affects heart rate, use the RPE scale instead and consult your healthcare provider for personalized exercise guidance.

Last updated: February 23, 2026