During aerobic exercise, the participant will subjectively evaluate how he or she is feeling, assessing his/her sense of effort. The sense of effort correlates with numbers on the Borg scale and the revised scale. For example, if the person feels the workout is extremely easy, he/she may rate the workout a "7" on the Borg scale or a "0.5" on the revised scale. For the general population, ratings of perceived exertion between 11-15 on the Borg scale and between 3-5 on the revised scale should be sufficient for fitness improvment.