Alternatives to Heart Rate Formulas
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I am using the manual approach to determining maximum heart rate: 220 minus age 56 equals 164. Using this number, I have been trying to train at three levels:
Stage 1 (easy): 60-70% of max, or 98-115 heart rate
Stage 2 (medium): 70-80% of max, or 115-131 heart rate
Stage 3 (hard): 85-90% of max, or 140-147 heart rate
My typical workout is to jog 4-5 miles three or four times a week at a pace of 9:30, which results in my heart rate averaging 150 or more. If I do interval workout, I can record 160 to 175, which exceeds my predicted maximum. What am I doing wrong? Should I be running longer at a slower pace. This almost too slow to produce any fitness benefits.
Please don’t feel insulted, but this is a case of “garbage in; garbage out.” Your predicted maximum heart rate based on the 220 minus age formula probably is not accurate. Formulas don’t work for everyone. When I was age 30, my predicted maximum heart rate based on this formula would have been 190. But my true max, based on numerous tests at the Ball State University Human Performance Laboratory, was 160! I had a large heart, a strong pumping beat and a very low pulse rate of 29, one reason for my success as an endurance athlete.
Given your heart rate of 175 during an interval workout, I suspect that if we sent you to Ball State, the scientists would probably determine that your max was somewhere between 180 and 190. It is usually difficult for all but the best trained runners to achieve 95% of max in an interval workout. In a 10-K race where you sprinted in the last quarter mile, maybe you might see your numbers plateau, suggesting you had reached 100%, but again, not everyone can do this.
Rather than planning your workouts around what appear to be false numbers, try experimenting with Perceived Exertion. In other words, run easy, medium or hard and see what your heart monitor offers after the workout. The other alternative would be to schedule a stress test where the medical people allow you to run on a treadmill until you achieve a true maximum. Probably not a bad idea for a person your age anyway.