Energy sources

The energy sources breakdown shows how much of different energy sources (carbohydrates, proteins, fats) you used during your session. This information is available in the Polar Flow mobile app after syncing your data.

Energy sources are shown in the Flow app’s training analysis view for automatically recorded training sessions.

During physical activity, your body uses carbohydrates and fat as main sources of energy. The higher your training intensity, the more carbs you use in proportion to fat, and vice versa. The role of protein is usually quite small, but during high intensity activity and during long sessions your body can use about 5 to 10 % of its energy from protein.

We calculate the use of different energy sources based on your heart rate, but we also take your physical settings into account. These include your age, gender, height, weight, maximum heart rate, resting heart rate, VO2max, aerobic threshold and anaerobic threshold. It's important that you've set these settings as precisely as possible so you'll get the most accurate energy source consumption data.

Energy Sources in the Flow App

In the Flow app you can see how much carbohydrates, protein, and fat you used during your session. You can also see how much of these sources you used at each point of your session and how they accumulated throughout it. The graph shows how your body makes use of different energy sources at different training intensities, and also at different stages of your training session. You can also compare the breakdown from similar sessions over time, and see how your ability to use fat as the primary energy source develops.

Note that you shouldn't interpret the used energy sources and their amounts as guidelines when eating after your session.

Learn more about energy sources.