Estimate exercise energy expenditure using the Compendium of Physical Activities MET database standards.
A clinical exercise physiologist designing a cardiac rehabilitation program monitors their patients' MET targets to regulate workload safety. Calorie counting serves as the basis for weight management, but understanding the metabolic cost of activities helps tailor cardiovascular conditioning programs.
Energy expenditure during exercise represents the heat generated by muscles converting food (glycogen and lipids) into mechanical work. We measure this energy in kilocalories (kcal), representing the physical cost of your workouts.
The body burns fuel primarily via aerobic respiration, which requires oxygen. For every liter of oxygen your body consumes, it generates approximately 4.86 calories of heat energy. By tracking oxygen consumption (VO2), exercise scientists can calculate exact caloric burn. Submaximal testing estimates this cardiorespiratory cost using MET values.
A Metabolic Equivalent (MET) represents a unit of relative metabolic rate. Sitting quietly at rest has a physiological cost defined as **1 MET** (equivalent to consuming 3.5 ml of oxygen per kilogram of body weight per minute: `3.5 ml/kg/min`).
High-intensity workouts trigger Excess Post-Exercise Oxygen Consumption (EPOC). After intense training (like heavy lifting or sprinting), your body continues to consume elevated levels of oxygen to replenish glycogen stores, buffer lactic acid, and lower core temperature. This elevated metabolic rate continues to burn calories for several hours post-workout.
The calculation is: `kcal = METs × 3.5 × weight_kg / 200 × duration_mins`. MET-hours are calculated as `METs × (duration / 60)`. Absolute oxygen is calculated as `(METs × 3.5 × weight_kg × duration) / 1000` (Liters).
Fitness trackers frequently overestimate calorie burn by 20% to 40% because they often count baseline BMR calories twice, or use generic algorithms that over-estimate active heart rate calorie conversions.
Yes. Muscle tissue is highly active metabolically. Individuals with higher muscle mass require more oxygen to perform the same workload, resulting in a slightly higher calorie burn than predicted by standard weight formulas.
Steady-state cardio (like running or cycling) typically burns more calories per minute *during* the workout. However, heavy lifting builds muscle tissue (elevating resting metabolic rate) and triggers a larger EPOC effect post-workout.
VO2 Max Calculator — Computes maximum oxygen utilization index.
Heart Rate Zones — Establishes heart rate target ranges.
Running Pace Calculator — Calculates splits and paces.