Anaerobic Threshold Calculator

Enter your age to calculate your anaerobic threshold heart rate and full heart rate training zones. Based on the Fox & Haskell formula (BPMmax = 220 − age), this tool returns your maximum heart rate, anaerobic zone (80–90% of max), and all five training zones from recovery to VO2 max. You can also enter a known anaerobic threshold BPM to reverse-calculate your expected age.

Disclaimer: This tool is for informational and educational purposes only. It is not a substitute for professional medical advice, diagnosis, or treatment. Always consult a qualified healthcare provider before making any health-related decisions.

years

Your current age in years

BPM

Enter a known threshold BPM to reverse-calculate expected age

Results

Anaerobic Zone (Lower Bound)

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Maximum Heart Rate (BPMmax)

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Anaerobic Zone (Upper Bound)

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Expected Age (from threshold BPM)

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Results Table

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Frequently Asked Questions

What heart rate is anaerobic?

The anaerobic heart rate zone is typically between 80% and 90% of your maximum heart rate. At this intensity, your body produces energy faster than it can use oxygen, leading to lactate buildup. For a 30-year-old with a max HR of 190 BPM, the anaerobic zone is roughly 152–171 BPM.

What formula does this anaerobic threshold calculator use?

This calculator uses the Fox & Haskell formula: BPMmax = 220 − age. Your maximum heart rate is then used to calculate each training zone as a percentage of that max. It's the most widely used method for estimating max heart rate from age alone.

What affects anaerobic threshold?

Anaerobic threshold is influenced by fitness level, genetics, training history, and overall cardiovascular health. Regular high-intensity interval training (HIIT) can raise your anaerobic threshold over time, allowing you to sustain higher intensities before lactic acid accumulates.

How long can you sustain anaerobic heart rate?

Most people can sustain the anaerobic zone (80–90% of max HR) for only a few minutes at a time. Beyond that, lactate accumulates faster than the body can clear it, leading to fatigue. Elite athletes can push this threshold higher and sustain it longer through training.

What is a heart rate?

Heart rate is the number of times your heart beats per minute (BPM). It reflects how hard your cardiovascular system is working. Resting heart rate for most adults is 60–100 BPM, while maximum heart rate varies by age and fitness.

How do I measure my heart rate?

You can measure heart rate manually by counting pulse beats at the wrist or neck for 15 seconds and multiplying by 4. Alternatively, use a heart rate monitor, fitness tracker, or smartwatch for continuous real-time measurement during exercise.

What are the five heart rate training zones?

The five zones are: Recovery (50–60% of max HR), Endurance (60–70%), Aerobic (70–80%), Anaerobic (80–90%), and VO2 Max (90–100%). Each zone targets different physiological adaptations, from fat burning and base fitness to peak performance.

Can I use this calculator in reverse?

Yes. If you already know your anaerobic threshold BPM from a lab test or fitness assessment, you can enter it in the optional field and the calculator will estimate the expected age corresponding to that threshold based on the Fox & Haskell formula.