Exercise intensity refers to how difficult an exercise is, and will vary from one person to the next based on fitness level and experience. Quantifying exercise intensity can be useful for evaluating whether you are exercising hard enough to get a training effect that will help you become stronger and manage your weight.
Individualizing Exercise Intensity
When establishing exercise guidelines, health and fitness professionals often make recommendations based on intensity. For example, the American College of Sports Medicine recommends all Americans younger than age 65 perform 30 minutes of moderate-intensity exercise daily. But the term moderate is subject to interpretation. To more specifically quantify intensity for cardiovascular and resistance exercise, you can do some basic assessments and crunch some numbers.
Calculating Cardiovascular Exercise Intensity
To quantify cardiovascular intensity, a mathematical formula known as the heart rate reserve or HRR formula is the most user friendly. The formula gives you a training zone known as your target heart rate range based on your maximum and resting heart rates. Take your resting heart rate, or RHR, first thing in the morning by counting your pulse beats for a full minute. To determine maximum heart rate, or MHR, subtract your age from 220. Plug those values into the formula: [(MHR-RHR) X (% intensity)] + RHR. Work the equation twice, once for the low end of the range and once for the high end, then monitor your heart rate during exercise to stay within that range. For low to moderate intensity, calculate in the 50 to 60 percent range. For moderate to challenging intensity, stay between 60 and 75 percent and for high intensity, calculate between 75 and 90 percent.
Calculating Strength Exercise Intensity
Resistance training intensity is typically based on a percentage of your one-rep max, or 1RM, which is the maximum weight you can lift one time. Weight training sets that fall under the ACSM guidelines of eight to 12 repetitions are generally based on a 70 percent value of your 1RM. To determine your 1RM, you could attempt to lift as much weight as possible for a given exercise and then work the percentage. However, unless you are extremely fit, doing so could cause injury. Instead, experiment to see how much you can lift in the eight to 12 rep range, fatiguing the muscle within that range. If you can do more than 12, increase the weight. If you cannot do eight, decrease the weight.
Rating Intensity Based on Perceived Exertion
If math is not your forte, the American Council on Exercise recommends using rating of perceived exertion, or RPE. This method lets you evaluate your exercise intensity based on how you feel by rating your perceived level of exertion on a scale of zero to 10, with zero representing no exertion at all and 10 representing an all-out effort. Using this method, moderate intensity falls within the three to five ranking, challenging intensity falls in the six to eight range, and high intensity falls in the eight to 10 range. RPE can be used for both cardiovascular and strength training.
References
- American College of Sports Medicine: Physical Activity and Public Health Guidelines
- Sports Fitness Advisor: Heart Rate Reserve... How to Determine Your Heart Rate Training Zone
- Bodybuilding.com; A Quasi-Comprehensive Definition and Explanation of Intensity; David Knowles
- National Academy of Sports Medicine: APPENDIX 5: Percent of One Rep Maximum (1RM) Conversions
- American Council on Exercise: Monitoring Exercise Intensity Using Rating of Perceived Exertion
- TopEndSports: Rating of Perceived Exertion (RPE) Table
Member Comments