What You'll Learn

What MET means and why Gymkee uses it
How Gymkee calculates calories for your activities
How workout calories are estimated after a strength training session
Why your body weight, intensity level, and wearable data all matter
Tips for getting the most accurate calorie numbers

What Is MET?

MET stands for Metabolic Equivalent of Task. It measures how hard your body is working compared to sitting still.

Sitting on the couch = 1 MET. Walking at a normal pace = about 3.8 MET. Running = anywhere from 6.5 to 14.8 MET depending on speed. In other words, the higher the MET, the more energy you burn.

Gymkee uses MET values from the Compendium of Physical Activities, a research database used worldwide. Every activity type in Gymkee has a MET value assigned for each intensity level, so the calorie estimate adapts when you change from Moderate to High intensity.

How Gymkee Calculates Calories for Activities

When you log an activity (running, cycling, swimming, tennis, etc.), Gymkee calculates the calories burned with a straightforward formula:

Calories = MET x your weight (kg) x duration (hours)

Here is a concrete example. If you go for a moderate-intensity run (MET 9.3), you weigh 75 kg, and you run for 45 minutes (0.75 hours):

9.3 x 75 x 0.75 = 523 calories

Three things directly affect this number:

Activity type and intensity. A moderate run (MET 9.3) burns far more than moderate yoga (MET 3.0). Choosing the right activity type and intensity is key.
Your body weight. A heavier person burns more calories for the same activity and duration. This is simple physics: more mass to move = more energy required.
Duration. Longer sessions burn more. The relationship is linear: double the time, double the calories.

Intensity Levels

Every activity in Gymkee has up to three intensity levels:

Low (Faible): Easy effort. You can hold a full conversation without trouble.
Moderate (Modérée): Comfortable effort. You can talk in short sentences.
High (Élevée): Hard effort. You can barely get a few words out.

Changing the intensity recalculates the calories automatically because each level uses a different MET value. For example, cycling outdoors goes from MET 4.0 (Low) to MET 8.0 (Moderate) to MET 12.0 (High). That is a 3x difference between easy and hard.

How Workout Calories Are Estimated

Strength training (séances on Gymkee) is different from cardio activities. A squat, a bicep curl, and a burpee all have different energy demands. Gymkee uses a more sophisticated approach with a 4-layer priority system:

Layer 1: Wearable data (best accuracy)

If you wear an Apple Watch, Garmin, or other connected device during your workout, Gymkee reads the active energy directly from Apple Health or Google Health Connect. This is the most accurate source because the wearable uses your real-time heart rate and motion data.

Layer 2: Heart rate formula

If wearable calorie data is not available but heart rate data is, Gymkee applies the Keytel 2005 formula. It takes your average heart rate during the session, your weight, age, and gender to compute calories. If your wearable also has a VO2max reading (from the last 90 days), that gets factored in for even better accuracy.

Layer 3: MET-based workout estimate

If no wearable data is available at all, Gymkee analyzes the actual workout you completed:

Each exercise gets a MET value based on its name and type (heavy compounds like squats get a higher MET than isolation exercises like curls)
The load you lifted is factored in (heavier weights relative to your body weight = more energy)
Rest periods between sets are accounted for at a lower MET
Warm-up time is included
An afterburn factor (EPOC) of 10% is added for the elevated metabolism after your session
Gender and body composition are applied as corrections

This calculation only counts exercises and sets you actually completed. Skipped exercises do not count.

Layer 4: Coach estimate (fallback)

If none of the above produces a result, Gymkee may fall back to a pre-workout estimate if your coach configured one.

The system tries each layer in order and uses the first one that returns a valid number. You do not need to configure anything. It happens automatically.

When Wearable Data Takes Priority

If you sync your wearable (Apple Watch, Fitbit, Garmin, Samsung, Whoop, Polar, and others), imported activities bring their own calorie data straight from the device sensors. In that case, Gymkee uses the wearable's number rather than the MET estimate.

You can tell the difference in the activity detail screen:

MET-estimated calories are calculated by Gymkee based on the formula
Wearable calories come directly from your device

Both are displayed as approximate values because no method of calorie estimation is 100% precise.

Tips for Getting Accurate Calorie Data

Keep your body weight updated. Gymkee uses your weight in every calorie calculation. If your profile says 70 kg but you actually weigh 85 kg, every number will be off. Check your weight in your profile and update it regularly.
Choose the right intensity level. When logging an activity manually, be honest about the intensity. Picking "High" when your effort was moderate inflates the number significantly.
Wear a connected device during workouts. Wearable data (especially with heart rate) is more accurate than any formula. If you have a smartwatch, make sure Gymkee has permission to read health data.
Pick the correct activity type. Running and walking have very different MET values. Choosing the wrong type gives you a wrong estimate.
Fill in your profile completely. Your weight, height, age, and gender all influence calorie calculations. Gymkee uses defaults (70 kg, 175 cm, 30 years old) if this info is missing, which may not match your body.

Common Mistakes

Leaving your weight blank or outdated. Gymkee defaults to 70 kg if no weight is set. If you weigh more or less than that, your calorie numbers will be inaccurate.
Always selecting "High" intensity. It is tempting to pick the highest level, but if your actual effort was moderate, the calorie estimate will be inflated.
Comparing Gymkee numbers to your Apple Watch numbers. Different devices and apps use different formulas, heart rate algorithms, and sensor data. Some variation between Gymkee and your watch is normal and expected.
Treating calorie estimates as exact numbers. All calorie calculations (including from wearables) are estimates. Use them to compare workouts and track trends, not as precise accounting.

Troubleshooting

Problem: My calorie count seems too low

Why it happens: Your body weight in Gymkee might be lower than your actual weight, or the intensity level is set to Low when your effort was higher.

How to fix it: Go to your profile and update your weight. When logging activities, choose the intensity that matches your actual effort level.

Problem: My calorie count seems too high

Why it happens: You may have selected a high-intensity activity type when the actual effort was lower, or your profile weight is higher than your actual weight.

How to fix it: Double-check the activity type and intensity. Edit the activity to adjust if needed.

Problem: My workout shows no calories

Why it happens: You may not have completed any exercises during the workout (all sets skipped), or your profile has no weight data and the calculation could not run.

How to fix it: Make sure you mark sets as done during your workout. Also check that your weight is set in your profile.

Problem: Gymkee and my Apple Watch show different numbers

Why it happens: Apple Watch uses its own algorithm with real-time heart rate, movement sensors, and Apple's proprietary formulas. Gymkee uses MET-based calculations for manual entries or the raw Apple Health data for synced activities. The two approaches naturally produce different results.

How to fix it: This is expected. Neither number is "wrong." If you prefer the Apple Watch number, make sure health sync is enabled so Gymkee uses the wearable data directly.

FAQ

Is MET the same as calories? No. MET is a measure of intensity (how hard you are working). Calories are the energy you actually burn. Gymkee multiplies MET by your weight and duration to convert intensity into calories.

Why does a heavier person burn more calories? Because it takes more energy to move a heavier body. The formula includes your weight directly: more weight = more calories burned for the same activity and duration.

Can I manually enter my own calorie number? When you log an activity, Gymkee estimates calories automatically based on the activity type, intensity, duration, and your weight. You cannot override this number manually.

Are the 12 activity categories all MET-based? Yes. Gymkee has 12 categories (Running, Cycling, Swimming, Strength, Team Sports, Racquet Sports, Combat, Outdoor Adventure, Water Sports, Flexibility, Dance, Other) with over 75 activity types. Each type has MET values from the Compendium of Physical Activities.

What is EPOC (afterburn)? EPOC (Excess Post-exercise Oxygen Consumption) is the extra energy your body burns after an intense workout as it recovers. Gymkee adds a 10% afterburn factor to workout calorie estimates.

What if I do not have a wearable? No problem. Gymkee calculates calories using MET formulas. The estimates are research-backed and reliable for tracking trends. A wearable adds more precision, but it is not required.