Exercise intensity doesn’t come in “one size fits all”— it can even be as individual as choosing the best way to eat an Oreo (never ever take the cookie apart, of course). Perceived intensity is different for everyone, but studies suggest the higher the heart rate during physical activity, the higher the intensity .
Ticker Time — The Need-to-Know
Heart-rate training (which can be done in a variety of ways) can determine if the aerobic activity is too light, too hard, or just right (just like Goldilocks). To determine exercise intensity manually, a little math is necessary to figure out the ideal target heart rate. Knowing this number will help determine if the body is working at the correct speed for specific workout goals. Keeping that number in mind, find the carotid (neck) or radial (wrist) artery with the index and middle finger, count the pulse for six seconds, and multiply by 10 to figure out the heart rate (or beats per minute). And for the techies among us, there’s always a gadget (or an app) for that. Heart rate monitors are devices that make contact with the skin, read, and then display the heart rate. There is also the RPE (Rated Perceived Exertion) to measure intensity, where intensity is based on a scale of zero to ten , with ten being all out maximum effort, six being moderate intensity, and zero signifying a potato sitting on a couch somewhere.
But other research suggests 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 to monitors measuring heart rate and intensity. Then they were 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 there is a close correlation between the talk test and the heart rate measurements, suggesting 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’s 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 who have more ambitious fitness objectives (like, say, are going for their 3rd Olympic medal), being able to carry on a casual conversation may mean exercise is not intense enough .
Look Who’s Talking Now — Your Action Plan
The talk test works because talking comfortably means 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  (The latest American College of Sports Medicine exercise recommendations say that aiming for 30 minutes a day of simple, moderate-intensity exercise is the way to go to improve general health ). If the words don’t flow as easily (where a breath is required after every word), the workout crosses over into the vigorous range . And on the flip side, if singing show tunes is involved, the workout may be too easy, and the heart isn’t working hard enough .
Hitting the target heart rate is important to any aerobic activity, and with the talk test there is no need to revisit seventh grade math (hey, calculating heart rate can be tricky!) and no need to spend any money. All it requires are vocal cords and the ability to talk, talk, 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. The best part is there are no failing grades with this test!