Borg Perceived Exertion Scale

The Borg Perceived Exertion Scale gives you an idea of how hard your exercise feels. If it feels light (less than 12), you should increase the pace of your exercise, walking, biking, swimming, etc. If the exercise feels hard (14 or greater, you need to slow the pace. Exercise should feel somewhat hard (12-13). Borg's Scale:

6
7		very, very light
8
9		very light
10
11		fairly light
12
13		somewhat hard
14
15		hard
16
17		very hard
18
19		very, very hard
20