Or I can use the Karvonen formula; 220 minus 64 = 156, minus my resting heart rate of 52 = 104 called heart rate reserve. Then, multiply 104 x 65% and add 52 for a total of 120 beats per minute.
So if I wish to train in the 65% "zone", one formula tells me 101 beats per minute and another tells me 120. That's like shooting and then calling whatever one hits the target. The Journal of the American Society of Exercise Physiologists compiled 43 heart rate calculation methods. When one refers to aerobic training zones it is almost comical. Real world applications are peaks of effort and valleys of recovery.
Dr. Fritz Hagerman, an exercise physiologist at Ohio University, said he had learned from more than three decades of studying world class rowers that the whole idea of a formula to predict an individual's maximum heart rate was ludicrous. Even sillier, he said, is the common notion that the heart rate is an indication of fitness.
Human beings love to inject precision into imprecise situations. It gives us a sense of order. Yet no one can assign training zones for another. This is why the concepts of training zones, steady state cardio and high intensity interval training miss the point. Only the individual knows how much effort is appropriate for their level of fitness.
This Rate of Perceived Exertion concept was used to develop the Borg scale which relies on how the trainee perceives his work effort. I cannot imagine a person who does not know instinctively when he or she is training too hard or too easy. If one can speak comfortably while exercising, the rate is at the low end of their cardiovascular training spectrum. If one is breathing so hard he couldn't tell the paramedics where it hurts, assume that's a tad too high. It's impossible to maintain any sort of maximum effort too long. The body will cease the activity on its own or have a heart attack. And the whole point of cardio is to strengthen the heart, not rupture it. No formula can fix stupid.
I own an "Insta-Pulse" which is a baton shaped item about eleven inches long. It replaces the chest band / wrist readout used by other manufacturers. To measure the pulse, one holds the baton in both hands and in a second or two the pulse is displayed on the digital readout. I can read it without bi-focals which is a big plus since I do not wear my glasses during a workout. I added a cord to the wrist lanyard and suspended the Insta-Pulse at a corner of my training floor. I can quickly grab it, take a reading and continue.
This toy is addictive. My morning pulse ranges from 49 to 55 beats. That's supposed to be very good even though I resemble the Michelin Man. I imagine my heart has become strong from squeezing butter laden blood through my arteries over 64 years. During karate workouts my pulse never drops below 110, averages 130 and I crack the 150 mark several times. I guess this means I am doing both endurance cardio and high intensity. Sort of like belonging to multiple religions to cover all the bases when I die.
I like the Insta-Pulse. It tells me exactly what my pulse rate is and this knowledge provides relevance. If I can perform the same amount of work in the previous time with a lower pulse rate, I must be getting fitter. If my resting pulse rate drops, my heart must be working more efficiently. If I am able to sustain a higher heart rate, improvement has taken place. The actual numbers mean little, they only provide benchmarks from which to judge progress or decline.
But something worried me. I couldn't quite grasp what. Weeks went by. Then it hit me......holding the Insta Pulse Baton between my hands and looking down........... is what Petie the parakeet must have seen in his final moments.