Exercise intensity is an important part of your exercise program. Working at the right intensity can mean the difference between weight and health improvements or wasted efforts. You can judge your intensity in respect to your own fitness level or as a generalization. Others may need to use their own feeling to rate their intensity.
Absolute intensity is a general measurement of intensity applied to anyone, independent of any factors. It is usually measured as a metabolic equivalent, or MET, states the United States Department of Health and Human Services. A MET is a measurement of energy. One MET is the amount of energy any human uses in a resting state, like sitting or sleeping. The more METs you are working at, the higher the intensity of exercise. If you are exercising at 3 METs, you are using three times the amount of energy you use at rest. Light intensity is work up to 2.9 METs, moderate intensity extends from 3 to 5.9 METs and high intensity activity is greater than 6 METs.
Relative exercise intensity is specific to your level of fitness. A relative exercise intensity is based off of your own maximum capability of work. For example, a percentage of your maximum heart rate or maximum oxygen uptake, both of which are signs of fitness. It is more specific to each person and can be tailored to enhance health and wellness.
Rating of Perceived Exertion
Relative intensity can also be based upon a person's rating of perceived exertion. This is your own personal evaluation of how the intensity of your activity feels to you. It is not based on any feedback from your body other than the amount of work you perceive yourself as participating in. Rating of perceived exertion, or RPE, is based on a scale that extends from 6 to 20, varying from light work to extremely hard work. Moderate exercise falls around a 12 or 13 on the RPE scale. You might consider using RPE to judge relative intensity if you are on medication that can affect how your heart rate responds to exercise or if you do not have the means to monitor your heart rate.
Relative intensity is a better way of measuring your intensity because it is more specific to your abilities. The need to monitor intensity is essential, regardless of whether it is absolute or relative. The intensity of your program is largely dictated by your goals. For example, improvements in blood pressure can be seen with just moderate intensity exercise, but for someone wishing to improve bone health, high intensity exercise may be needed. Whether you use relative or absolute intensity, seek clearance from your doctor before participating in an exercise program. He may even be able to guide you into the right intensity for your goals and medical history.
- U.S. Department of Health and Human Services: Physical Activity Guidelines for Americans
- ExRx: Aerobic Exercise Prescription
- Centers for Disease Control and Prevention: Perceived Exertion
- "Medicine and Science in Sports and Exercise"; Absolute Versus Relative Intensity of Physical Activity in a Dose-Response Context; R.J. Shephard; June 2001