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Calories Burned by Heart Rate Calculator

Estimates energy expenditure during aerobic exercise from average heart rate, sex, age and weight (optionally VO2max) with the regression equations of Keytel et al. (2005), reporting calories per minute, per hour and for the whole session.

When to use

You have an average heart rate from a monitor for a steady aerobic session and want a calorie estimate, with or without a known VO2max.

Do not use when: You know the activity and want a MET-based estimate (use calories-burned), the session was intervals or strength work or outside the 90–150 bpm steady-state range, or the person takes heart-rate-altering medication; informational only.

Formula

Without VO2max: male kcal/min = (−55.0969 + 0.6309·HR + 0.1988·weight_kg + 0.2017·age_years) / 4.184; female = (−20.4022 + 0.4472·HR − 0.1263·weight_kg + 0.074·age_years) / 4.184. With VO2max: male = (−95.7735 + 0.634·HR + 0.404·VO2max + 0.394·weight_kg + 0.271·age_years) / 4.184; female = (−59.3954 + 0.45·HR + 0.380·VO2max + 0.103·weight_kg + 0.274·age_years) / 4.184. calories_burned = kcal/min × duration_minutes

Keytel et al. (2005) fitted these linear equations to indirect-calorimetry energy expenditure of adults during steady-state treadmill and cycle exercise; the VO2max version is the more accurate of the two. They apply to steady aerobic work at roughly 90–150 bpm and can give unrealistic (even negative) values outside that range. Informational only.

Inputs

ParameterTypeUnitRequiredDescription
sexenum: male | femaleyesSex category used to select the formula coefficients.
age_yearsnumberyearsyesAge in years (the equations were fitted on adults). Range: ≥ 10, ≤ 100
weight_kgnumberkgyesBody weight in kilograms. Range: > 0, ≤ 300
average_heart_rate_bpmnumberbpmyesAverage heart rate over the session (valid range about 90–150 bpm). Range: ≥ 60, ≤ 220
duration_minutesnumberminyesExercise duration in minutes. Range: > 0, ≤ 1440
vo2max_ml_kg_minnumberml/kg/minnoOptional measured or estimated VO2max; when given, the more accurate VO2max-inclusive equation is used. Range: ≥ 10, ≤ 100

Outputs

OutputTypeUnitDescription
calories_burnednumberkcalEnergy expenditure for the whole session.
calories_per_minutenumberkcal/minEnergy expenditure rate from the Keytel equation (kJ/min ÷ 4.184).
calories_per_hournumberkcal/hcalories_per_minute × 60.
kj_per_minutenumberkJ/minThe raw Keytel regression value in kilojoules per minute.
method_usedstringWhich Keytel equation (sex, with or without VO2max) was applied.
validity_notestringWhether the heart rate lies in the 90–150 bpm range the equations were derived for.

Example

Male, 30 y, 80 kg, 150 bpm, 45 min: {"sex":"male","age_years":30,"weight_kg":80,"average_heart_rate_bpm":150,"duration_minutes":45} → {"calories_per_minute":14.7,"calories_burned":661.4,"calories_per_hour":881.8,"method_used":"Keytel et al. 2005, male, without VO2max"}

Female, 40 y, 62 kg, 135 bpm, 30 min, VO2max 40: {"sex":"female","age_years":40,"weight_kg":62,"average_heart_rate_bpm":135,"duration_minutes":30,"vo2max_ml_kg_min":40} → {"calories_per_minute":8.1,"calories_burned":243.1,"method_used":"Keytel et al. 2005, female, with VO2max"}

GET https://tttkmbb.com/api/v1/calculate/calories-by-heart-rate?sex=male&age_years=30&weight_kg=80&average_heart_rate_bpm=150&duration_minutes=45

Machine access

Sources

FAQ

How accurate is a heart-rate calorie estimate?

Individual error is typically ±15–20 %: heart rate also responds to heat, dehydration, caffeine and stress, and fitness changes the heart-rate/oxygen relationship (which is why supplying VO2max improves the estimate).

Can I use it for weight training or intervals?

No. Heart rate stays elevated between efforts without matching oxygen use, so the equations over-estimate for intermittent work.

Does this include resting metabolism?

Yes: the regression predicts gross expenditure, so subtract about 1–1.3 kcal/min if you want the extra calories above rest.

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