Intensity Check: How Hard Are You Exercising?
by Karen Asp
Sweat can be a good measure of how hard you have worked out. Sweating a lot means you have really worked. If you only sweat a little it may be because you stayed up too late the night before.
Sweat is a sign that your body is working to cool itself, but it is not always a sign of how hard you have worked. For that, you need to turn to three common ways of checking your intensity: the talk test, rating of perceived exertion (RPE), and target heart rate (THR).
Why It Matters
Intensity is simply a measure of how hard—or easy—you are working. Monitoring it matters for many reasons.
It lets you know if you are working too hard or not hard enough. Working too hard can cause overtraining which can lead to injuries, a decline in fitness performance, mood changes, lack of sleep, and other problems. But if you do not work hard enough it will take you longer to reach your fitness goals.
If you are recovering from an injury or illness, monitoring how hard you are working is also good way to make sure that you are not overdoing it.
Monitoring how hard you are working can also improve your performance. If you are training for a faster time in a 10K run, you will need to vary how hard your workouts are. Some days you will need to work harder than others.
Testing Your Intensity
How you monitor it is up to you. Here are three common ways:
The Talk Test
The talk test is easy to do. You should still be able to talk no matter how hard you are working out. You do not have to carry on a whole conversation, but you should be able to speak in broken sentences. If you are too winded and have to gasp for air, then you are working too hard. If you feel like you could talk for hours, then you are not working hard enough.
Rating of Perceived Exertion (RPE)
RPE measures how you feel and how hard you think you are working. You will need to be honest with yourself.
One method of RPE lets you rate your exertion on a scale that runs from 0 to 10. Most people should work out between a level of 3 and 5. Of course, the toughest part with this check is giving a scale number to how you are feeling. Lying in bed would rate a 0. If you run at full speed to catch a bus that is pulling away from the curb, you may rate yourself a 10.
Another RPE scale, the Borg scale, is a 14-point scale that rates exertion from 6 points (no exertion) to 20 points (maximum exertion). The Borg scale differs in that it may give you a fair estimate of your heart rate during physical activity. All you have to do is take your estimated RPE and multiply it by 10. An activity with a 12 would be multiplied by 10 and result in a heart beat per minute of 120.
Keep in mind that these scales are for your own level of exertion, not how you compare to others.
Target Heart Rate (THR)
THR is a popular way to measure intensity. It is the number of heartbeats per minute at which your heart should be beating during aerobic exercise. It can vary by person.
People in good health should work between 50% and 85% of their maximal heart rate—the highest heart rate you can achieve. If you are taking medicine, your range may be lower. Talk with your doctor to find out your recommended heart rates.
Finding Your Target Heart Rate
Subtract your age from 220 to find your estimated maximal heartrate. For example, if you are 30, your maximal heart rate is 190 beats per minute (bpm).
Finding your target heart rate is a little different. Multiply your maximal heart rate by 50% (for moderate physical activity) and you come up with 95 bpm. Multiply 190 by 85% (for vigorous physical activity) and you get 162 bpm. This means that after you have warmed up, you should try to keep your heart rate between 95 and 162 bpm. Stay toward the lower end if you are just starting an exercise program.
Calculating Your Heart Rate
You can use a heart rate monitor to find your heart rate. If you do not want to pay for a monitor, you can calculate it using palpation.
Use the fingertips of your first two fingers. Use light pressure to locate your pulse at one of these sites:
When you have found your pulse, count the number of beats for 10 seconds. Try to do this within 10 seconds after you have stopped exercising. While you are doing this, move around so that you do not get lightheaded.
Take your 10-second heart rate and multiply it by 6. What you have just found is the number of times your heart is beating per minute. If your 10-second count is 18, then your heart rate is 108 bpm.
Keep in mind that THR is just an estimate. Heart rates can often be affected by stress, medicines, fatigue, caffeine, and other things.
If you are new to exercise, monitor your intensity often during exercise, such as every 10 minutes. This will help you make sure that the level you are working at is safe for your age, fitness level, and medical status. You can monitor less often when you are used to how your body responds to exercise.
American College of Sports Medicine
American Council on Exercise
Canadian Society of Exercise Physiology
How to determine your optimal intensity for training. American Council on Exercise website. Available at: https://www.acefitness.org/education-and-resources/lifestyle/blog/5896/how-to-determine-optimal-intensity-for-hr-training. Accessed June 30, 2021.
Perceived exertion (Borg rating of perceived exertion scale). Centers for Disease Control and Prevention website. Available at: https://www.cdc.gov/physicalactivity/basics/measuring/exertion.htm. Accessed June 30, 2021.
Target heart rate and estimated maximum heart rate. Centers for Disease Control and Prevention website. Available at: https://www.cdc.gov/physicalactivity/basics/measuring/heartrate.htm. Accessed June 30, 2021.
Target heart rates chart. American Heart Association website. Available at: https://www.heart.org/en/healthy-living/fitness/fitness-basics/target-heart-rates. Accessed June 30, 2021.
Validating the talk test as a measure of exercise intensity. American Council on Exercise website. Available at: https://www.acefitness.org/certifiednewsarticle/888/ace-sponsored-research-validating-the-talk-test-as-a-measure-of-exercise-intensity. Accessed June 30, 2021.
Last reviewed June 2021 by EBSCO Medical Review Board
Last Updated: 6/30/2021
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