|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.