The notion that we need to train in a heart-rate “zone” has long been held, and a standard formula has been widely accepted to help us make sure we are in the right range for "cardiovascular" exercise.
This formula, which is calculated by 220 minus your age, theoretically represents your maximum heart rate.
There are several ways to calculate maximum heart rate, but there is no scientific basis for the formulas.
So what should the average exerciser who just wants to enjoy the benefits of cardiovascular exercise, but also wants to safely gauge his or her activity level do to make this process easier? One answer is to simply take the "talk test."
The concept of determining one's optimal training intensity by using a verbal/cognitive method may have first been recorded in history in 1939 as a professor at Oxford University in England admonished his student mountaineers to "climb no faster than you can talk." A study conducted in 2004 found a close correlation between VO2 max and recommended heart-rate ranges and the self-monitored ability to recite a familiar set of verses (most handily, the "Pledge of Allegiance").
Here's how you can determine your own optimal exercise intensity using the Talk Test:
- Use any exercise mode you are comfortable with (treadmill, stationary cycle, elliptical, etc.)
- Start out slowly. After 2 minutes at the same speed/intensity level, recite the Pledge of Allegiance (or any other set of memorized verses consisting of roughly the same length and same number of syllables). After reciting, ask yourself the question: "Was I able to speak comfortably?" If yes, increase the intensity of the exercise.
- After another 2 minutes, recite your verses again, and ask yourself again, "Was I able to speak comfortably?" If so, continue in the same manner until you are uncertain about your answer (you can’t decide if it was yes or no), which would indicate you are now at the point where the exercise is challenging enough, but not too much that you would not be able to continue for any length of time (say 20 or 30 minutes). This is where most beginners should stop increasing intensity and keep it there or slightly under for the duration of the workout.
- If the answer was definitely NO – that is, you know that you cannot comfortably speak at this point and must focus most of your energy on breathing, this means you are at the high end of your cardiovascular training level and will not be able to maintain this pace for much longer. Experienced exercisers and athletes with performance goals can work at this level without fear of trouble, for the most part.
As you can see, using this method is an easy, fairly accurate way to gauge not only a safe exercise range (because if you over exert yourself, you will simply be unable to talk) but also to easily adjust your intensity as your fitness and endurance improves. Just be sure to note the level you set on your cardiovascular machine, and if you can ramp it up without going over your talk limit, you know you are gaining in fitness. This is also ideal for people who may be on medications that alter their heart rate (for instance, beta blockers used to aid in hypertension control will slow the resting heart rate down, making the use of maximum heart-rate estimates much more inaccurate). Make sure to check with your physician or an experienced fitness instructor or trainer before starting any exercise program. Your doctor will recommend a stress test if warranted and may make his or her own recommendations for your exercise range, which you should adhere to if prescribed.
If you are reasonably healthy, go ahead, and talk up a storm (or breathe and talk a little bit). Of course, if you’re in the middle of a packed treadmill bank, other members in your gym may look at you in a funny way if you talk too loud so please keep the volume of your voice down. However, this is one case where talking to yourself is a good thing.