How GraphGains calculates calories burned during manual activities
When tracking manually entered activities like cycling or running, estimating calorie burn relies on a standardized scientific metric called MET (Metabolic Equivalent of Task).
Because the application lacks real-time physiological data (like heart rate) during manual entry, MET values provide a baseline for physical exertion. One MET is defined as the energy expended by the body while at rest. An activity with a MET value of 5, for example, requires five times the energy of resting.
To determine the calories burned per minute, the application takes the activity's specific MET value and factors in the user's body weight. The standard clinical formula is:
Calories per minute = (MET × 3.5 × Weight in kg) / 200
By multiplying this per-minute value by the total duration of the activity, the total session calories can be accurately projected.
The following table provides baseline estimations for common activities, calculated for an average user weight of 70 kg (154 lbs).
| Activity | Typical MET Value | Est. Calories / Min (70kg) |
|---|---|---|
| Walking (brisk, 3.5 mph) | 4.3 | ~ 5.3 kcal |
| Cycling (moderate, 12-14 mph) | 8.0 | ~ 9.8 kcal |
| Running (6 mph / 10-min mile) | 9.8 | ~ 12.0 kcal |
| Swimming (freestyle, moderate) | 7.0 | ~ 8.6 kcal |
| Weight Training (general) | 3.5 | ~ 4.3 kcal |
| Yoga (Hatha) | 2.5 | ~ 3.1 kcal |
To maximize accuracy in the manual entry feature, the application should prompt the user for their current weight and allow them to specify the intensity of the activity (e.g., slow, moderate, vigorous). Adjusting the intensity directly modifies the underlying MET value, leading to a much more personalized calculation.