Exertion refers to the effort and intensity of how the body physically works and uses energy. It involves the process of the body’s use of oxygen, production of body heat, and the pace of the heart rate during physical movements. The feeling of exertion can vary for individuals performing the same actions due to differing levels of cardiovascular fitness and strength.
One of the main components of measuring how the body is using energy is known as the rating of perceived exertion, but is more commonly referred to as the Borg scale. The Borg scale is typically made up of a numerical rating scale that ranges from 6 to 20. The lower end of the Borg scale represents absolutely no usage of energy, while the top is the maximum amount of energy a person can use without being able to physically continue. The optimal rating for everyday exercise for average exercisers who are not athletes generally falls in the moderate rating of 12, 13, or 14 on the Borg scale.
The Borg scale is a subjective rating that is dependent on the person performing the activity; for example, the amount of physical activity it would take for a professional athlete to rate his or her exertion of 20 on the Borg scale may be drastically more than for a sedentary person. One of the most common uses of exertion monitoring is to help a person build up his or her endurance and fitness levels. If a person regularly performs an exercise at a low Borg scale rating, it is less likely that he or she will greatly improve his or her physical fitness abilities; however, by monitoring the effort and intensity of a workout and continuously striving for a particular rating, such as 14 or 15, a person may be able to build more endurance and ensure he or she is keeping his or her heart rate up.
Keeping close track of physical exertion may also be important for those who have problems with their hearts. Using the Borg scale may help prevent those who have weakened hearts from physically overexerting themselves and putting too much strain on their hearts. This may help heart patients safely remain active if their doctors recommend stopping their physical activity once it reaches a certain rating on the Borg scale. Some patients' self-rating may match their actual heart rate intensity better than others, so a doctor may test a patient’s heart rate while he or she performs activity in order to verify if the person is accurately using the Borg scale. If not, a person may be more likely to work too hard and not know when to slow down during physical activity.