| RPE | Heart Rate (% Max) | Description | Talk Test
|
| Level 1 | < 80% | Active recovery | Able to have a chat |
| Level 2 | 80-89% | Aerobic threshold | Harder to breath but you can still talk if you concentrate |
| Level 3 | 90-94% | Tempo | Breathing is a challenge. Talking is possible but only just |
| Level 4 | 95-99% | Lactic threshold | Breathing hard. Conversation is nearly impossible |
| Level 5 | >100 | Aerobic capacity | Can’t talk without gasping for air. Just not possible for more than a few seconds |
The photo show one triathlete who has been riding an Alpine pass at level 5 while his companion rarely got above level 2.