Training load is an EPOC-based feature that helps you track the combined effort of all activities recorded with heart rate data. Your Garmin watch and the Garmin Connect™ online fitness community provide per-activity training load insights (available on newer devices) and a seven-day baseline, so you can see the immediate impact of each activity as well as your overall acute training load for the past week. Your chronic four-week training load is a load measure used internally to calculate other features, such as training status and training load focus.
EPOC helps measure the impact of physical activity on your body and how much your body needs to recover and adapt after the activity ends. It is the work your body does to restore dynamic balance, or homeostasis.
Oxygen consumed is an indirect measure of the amount of energy your body uses to recover and prepare for the next challenge. Physiologists and sports scientists measure how much additional oxygen your body uses after exercise compared to normal oxygen consumption to determine the direct impact of an activity on your body.
The Firstbeat analytics engine in your Garmin watch skilfully estimates excess post-exercise oxygen consumption (EPOC) in real time by analysing heartbeat data and applying advanced mathematical models and machine learning.
