Exercising at the proper intensity level stimulates your cardiovascular system and improves your cardiorespiratory endurance. Improved cardiorespiratory endurance is associated with better overall health and a reduced risk of chronic diseases. Gauging how you feel and monitoring your heart rate are two common ways to determine your cardiorespiratory exercise intensity. Check with your doctor before starting a new exercise program, especially if you have been sedentary for a long time.
Perceived Exertion Scale
The Borg Scale of Perceived Exertion, developed by Dr. Gunnar Borg in 1982, matches how hard you feel you are exercising with numbers on a scale from 6 to 20. No exertion would be rated as a 6, while a 20 would indicate you feel you are working very hard and cannot maintain this cardiorespiratory intensity for long. The Harvard School of Public Health reports that most moderate activities correspond to a number between 11 and 14 on the Borg scale and more vigorous activities usually rate 15 or higher.
Target Heart Rate Zone
To promote the health benefits associated with aerobic exercise, your heart rate during exercise should be between 50 percent and 85 percent of your maximum heart rate, the Centers for Disease Control and Prevention says. This range is called your target heart rate zone and can be calculated by first subtracting your age in years from 220. This is your estimated maximum heart rate. Multiply this number by 50 percent, or 0.5, to determine the lower end of your target heart rate zone. Multiply your estimated maximum heart rate by 85 percent, or 0.85, to determine the upper end of your target heart rate zone.
Monitor Heart Rate
Monitoring your heart rate and making sure you are exercising in your target heart rate zone is a widely used way to determine your cardiorespiratory exercise intensity. To check your heart rate, stop exercising briefly and find your pulse, either at the side of your neck or on the underside of your wrist. Use your index and middle fingers, count the number of beats for 30 seconds, then multiply by 2. This is your per-minute heart rate. Compare your heart rate during exercise with your target heart rate zone to see whether you need to increase or reduce your exercise intensity.
Cautions and Recommendations
If you experience abnormal shortness of breath or pain, or if you cannot exercise as long as you planned, your cardiorespiratory exercise intensity may be too high. Reduce your exercise intensity and slowly and gradually increase your intensity as your fitness improves. To promote general health and reduce your risk of chronic disease, the American College of Sports Medicine recommends at least 30 minutes of moderately intense aerobic exercise five days each week.
References
- American Council on Exercise: Heart Rate Zone Calculator
- Harvard School of Public Health: The Borg Scale of Perceived Exertion
- Centers for Disease Control and Prevention; Physical Activity for Everyone -- Target Heart Rate and Estimated Maximum Heart Rate; 2011
- Mayo Clinic; Exercise Intensity -- Why It Matters, How It's Measured; 2011
- American College of Sports Medicine; Physical Activity and Public Health Guidelines; 2007
