In what training zone would you be exercising at a vigorous to very hard intensity, where talking is limited to infrequent, short phrases?

The training zone characterized by vigorous to very hard intensity, where conversation is limited to infrequent, short phrases, aligns with Zone 3. In this zone, the heart rate is elevated significantly, leading to increased breathing difficulty that makes longer conversations challenging. Zone 3 typically corresponds to around 70-85% of an individual's maximum heart rate and is often described as a state where the exerciser feels like they are working hard but can still sustain the activity for a moderate duration.

In contrast, other zones represent different intensity levels. Zone 2, for example, is associated with a moderate intensity where talking can occur more freely, while Zone 4 and Zone 5 reflect much higher intensities that further restrict conversation, often to the point of being unable to talk at all. Zone 4 is typically aligned with 85-90% of maximum heart rate, and Zone 5 reaches above that, indicating an all-out effort where endurance is significantly challenged.