RPE values & explanations

0 Rest

1 Very light: 

You feel hardly any exertion.

2 Light:

Feels like you can maintain for hours. Easy to breathe and carry a conversation.

3 Moderate:

Feels like you could go on like this for a long time and have a conversation.

4 Somewhat heavy:

Breathing is difficult, short conversations are possible.

5 Heavy:

All in all still well feasible, but exhausting.

6 Breathing heavily, can hold short conversation:

Still somewhat comfortable, but becoming noticeably more challenging.

7 Very heavy:

Holding conversations feels uncomfortable.

8 Borderline uncomfortable:

It is still possible to speak single sentences, but coherent conversations are no longer possible.

9 Very very heavy:

Can barely breathe and speak only a few sentences.

10 Like in competition: 

Feels almost impossible to keep going. Completely out of breath, unable to talk. Cannot maintain for more than a very short time.