How To Measure Exercise Intensity


There is no “one size fits all” when it comes to exercise intensity.  While perceived intensity is different for everybody, research studies suggest that the higher the heart rate during physical activity, the higher the intensity.  Heart-rate training can determine if the aerobic activity is too hard, too easy, or just right.  This can be done in a variety of ways.


To determine exercise intensity manually, a little math is required to figure out your ideal target heart rate.  Knowing this number will help to determine if your body is working at the correct speed for specific workout goals.  Keeping that number in mind, find your radial artery (at the wrist) or your carotid artery (at your neck) with your index and middle fingers.  Count the pulse for 6 seconds, and multiply by 10 to figure out the heart rate (beats per minute).





If you don’t want to deal with the math, you can get a heart rate monitor , which are devices that make contact with the skin, read, and then display the heart rate.  You can also use the Borg Scale of Perceived Exertion which gauges how hard you are exercising.  This is a scale that goes from 6 to 20, with 6 being “no feeling of exertion,” and 20 being “very, very hard.”  Moderate activities fall in the 11 to 14 range (“fairly light” to “somewhat hard,” and vigorous activities usually rate a 15 or higher (“hard” to “very hard.”).  You can then multiply your Borg score by 10 to get your approximate heart rate for a particular level of activity.





But other research suggests that an easier way to measure intensity may also be just as accurate, and all it takes is a little bit of talking!  One study had healthy, moderately active people exercise while attached monitors measuring heart rate and intensity.  They were then asked to perform a “talk test” by reciting the Pledge of Allegiance at specific points in the exercise.  At moderate intensity, the subjects were able to speak at a comfortable rate, and when exercise intensity went above and below moderate, the ability to talk was well matched to the heart rate monitor readings.  It turns out that there is a very close correlation between the heart rate measurements and the talk test, suggesting that it’s an effective tool to monitor exertion and measure exercise intensity.



But talkers take note–while the talk test is easy and effective it is not one size fits all, and the chatter may need to change depending on fitness level or fitness goals.  New research adds a twist to all this talking.  For the newbie gym-goer, the standard talk test remains a good idea.  But for those of you who have more ambitious fitness objectives, being able to carry on a casual conversation may mean that exercise is not intense enough.



The talk test works because talking comfortably means that breathe frequency, which is related to heart rate, is under control.  Even though the talk test is subjective, being able to talk comfortably (and therefore breathe comfortably) indicates low to moderate intensity.  As mentioned in my previous blog post, according to the Centers for Disease Control, the recommended amount of exercise is 30 minutes of moderate activity a day for 5 days.  If the words do not flow as easily (where a breath is required after every word), then the workout crosses over into the vigorous range.



Hitting the target heart rate is very important to any aerobic activity, and with the talk test there is no need to revisit 7th grade math (what?–calculating heart rate can be tricky!), and there’s no need to spend any money.  All it requires are your vocal cords and the ability to talk by reciting a few verses from a favorite rhyme, saying, or song.  Choose timed intervals throughout the exercise and start talking, paying attention to how easily the words come out!


And as always, if you or someone you know needs some guidance in how to stay active, call me at (302)691-9055 or visit my website at to schedule your FREE 30 minute Discovery Visit to see how Physical Therapy can help. Don’t delay–schedule now!