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Nutrition
Calories burned during training
Strength training, HIIT, running, sport, treadmill: Azetta estimates your expenditure with MET values from the Compendium, the cost of running per kilo and per kilometre, and the ACSM equations. Here is every formula.
5 min read Updated October 9, 2026
The principle
Measuring precisely what a session burns requires a laboratory. Without one, the most widely used method is to give each activity a MET value — its intensity expressed as a multiple of resting expenditure — taken from the Compendium of Physical Activities, the reference table that lists several hundred of them. Azetta uses it for strength training, timed sessions and sports; for running and the treadmill, it uses more direct relationships with distance and speed.
The Azetta method
The MET formula
The result is rounded to the nearest kilocalorie. The weight is the one in your profile.
| Session | MET |
|---|---|
| Strength training | 5.0 |
| Timed sessions (HIIT, Tabata, circuit, EMOM, AMRAP, For Time) | 8.0 |
| Stretching | 2.3 |
| Warm-up and cool-down jog | 6.0 |
For a logged session, the duration is the time you actually spent (at least one minute). Total volume, number of sets or perceived effort do not change these calories.
Running
The cost of a run depends mostly on distance and hardly on speed: about 1 kcal per kilo of body weight per kilometre.
This is the engine's calculation for a planned run. During a GPS-tracked run, the live screen counts with the same value, 1 kcal × weight × distance covered, without the jog part; that figure is kept as it is in the summary, the history and the day's totals. A run logged without calories is counted by the engine with the same formula.
Sport
Each sport has its MET value, averaged over a session including breaks: 7.5 for combat sports, 7.3 for tennis, 6.0 for hiking, 3.5 for walking, 3.0 for yoga, for example — 76 sports in total. When you answer "Intensity" after your session, the MET is multiplied by 0.8 (easy), 1.0 (normal) or 1.2 (hard).
Treadmill and machines
On the treadmill, Azetta uses the ACSM metabolic equations, with speed S in metres per minute and grade G:
The walking formula is used below 7 km/h, the running one above. The default grade is 1%, which reproduces the cost of running outdoors. Rower, bike and elliptical use METs according to the chosen intensity (for example 4.8 / 7.0 / 8.5 for the rower).
What counts in your day
- A planned session counts as long as the day isn't over; as soon as you log a session, that is the one that counts, never both.
- A planned sport counts when you answer "done". Without an answer by the end of the day, it does not count: a session is never assumed to have been done.
- An activity imported from a watch or from Health keeps the calories of the original app when it provides them.
Why this choice
- The Compendium is the most complete public reference: it lets 76 sports be handled the same way, without a sensor.
- For running, the energy cost per kilometre is remarkably stable from one speed to another for the same runner — as Margaria's classic measurements showed. Counting in kilometres is therefore more accurate than counting in minutes.
- The ACSM equations take the grade into account, which matters a lot on a treadmill.
- Never assuming a session was done avoids inflating your calorie goal with training that didn't happen.
Limits
- A MET value is an average: two 60-minute sessions can differ a lot depending on breaks and load.
- Heart rate is not used for calories, nor is excess post-exercise oxygen consumption.
- Steps are not converted into calories: everyday walking is covered by the everyday-life factor of the calorie goal.
- Running ignores elevation (except on the treadmill and when hiking, where it is taken into account).
References
- Ainsworth BE, Haskell WL, Herrmann SD, et al. 2011 Compendium of Physical Activities: a second update of codes and MET values. Medicine & Science in Sports & Exercise, 2011;43(8):1575-1581.
- Margaria R, Cerretelli P, Aghemo P, Sassi G. Energy cost of running. Journal of Applied Physiology, 1963;18:367-370.
- American College of Sports Medicine. ACSM's Guidelines for Exercise Testing and Prescription, 11th edition. Wolters Kluwer, 2021.
- Jones AM, Doust JH. A 1% treadmill grade most accurately reflects the energetic cost of outdoor running. Journal of Sports Sciences, 1996;14(4):321-327.
- Hreljac A. Preferred and energetically optimal gait transition speeds in human locomotion. Medicine & Science in Sports & Exercise, 1993;25(10):1158-1162.