The general formula for the average person is 220-age times 60%
and times 90% of HRmax. For example, a 30-year old would calculate
his target zone using the above formula: 220-30=190.
190x.60=114 and 190x.90=171. This individual would try to
keep his heartrate between 114 (low end) and 171 (high end)
beats per minute.
from Evelyn Mitchell firstname.lastname@example.org
The Karvonen Formula calculates your heartrate reserve range. To calculate it, take your pulse for one minute on three successive mornings upon waking up. (We will be using the case of a 30-year old male whose resting pulse was 69,70 and 71 for an average of 70 over the 3 days.)
Calculate target heartrate by subtracting your age from 220 (220-30=190).
Subtract your average resting heart rate from target heartrate (190-70=120).
The lower boundary of the percentage range is 50% of this plus your resting heart rate [(120 x .5) + 70 = 130]. The higher boundary is 85% plus your RHR [(120 x .85) + 70 =178]. Using the Karvonen Formula for percentage of heartrate reserve, this 30-year old man should be working between 130 and 178 BPM.
Like the maximum heartrate formula, the Karvonen formula can vary from individual to individual. Not every individual is "average", and there can be large differences among people. Therefore heartrate alone may not be the best indicator of how hard or how well you are working.
It is important to note that the deviation in both the age-specific formula and the Karvonen formula is due to the estimation of HRmax. If you have an actual HRmax from a graded exercise test, it will be more accurate. ACSM lists two formulas for estimating HRmax, each one with a standard deviation of +/- 10-12 BPM:
HRmax = 220 - age (low estimate) HRmax = 210 - (0.5 * age) (high estimate)
HR = exercise intensity * HRmax * 1.15
Source: ACSM's Guidelines for Exercise Testing and Prescription, 5th Edition, p. 274, Williams and Wilkins
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