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# Q. How do I measure resting and exercise heart rates? What is the Karvonen Formula?

A: The resting heart rate is most accurately assessed when measured for a full minute first thing in the morning before you get out of bed. Place your finger tips on the side of your neck (carotid pulse) or at your wrist on the thumb side (radial pulse). Avoid using too much pressure when using the carotid pulse to measure heart rate.

To measure exercise heart rate, count the pulse for six seconds and add a zero to obtain the approximate heart rate. For example, if 14 beats are counted, this would equate to a heart rate of approximately 140 beats per minute (bpm).

For a slightly more accurate monitoring, count the pulse for 10 seconds and multiply by six. For example, if you count 24 beats, multiplying this by six would equate to a heart rate of approximately 144 bpm.

To determine a training heart rate using the Karvonen Formula:

Determine the following heart rate parameters in beats per minute (bpm):

Resting Heart Rate (RHR): your pulse at rest (most accurate when measured for a full minute first thing in the morning before you get out of bed)

Maximum Heart Rate (MHR): this is either (a) measured during a maximal exercise test OR (b) estimated by subtracting age from 220 (220 – age = MHR). The ‘’220-Minus-Age’’ prediction equation for estimating MHR has an average error rate of plus or minus 12 bpm.

Heart Rate Reserve (HRR) = MHR – RHR

Determine the lower and upper end of the training zone based on the individual’s current level of fitness as determined by a fitness evaluation. For example:

Low level of fitness: 45-55%
Fair level of fitness: 55-65%
Good level of fitness: 65-75%
Excellent level of fitness: 75-85%

These are only examples and NOT absolute recommendations for training zones as they pertain to fitness level. It is common, however, to utilize a 10% range.

Calculate the training zone (example using 55-65% training zone range):

1. HRR x .55 + RHR = Lower end of the training zone
2. HRR x .65 + RHR = Higher end of the training zone

Practical Example:

Calculate the training heart rate of a 35-year-old female with a resting heart rate of 70. She has a high level of fitness based on the results of her fitness evaluation.

1. RHR = 70 bpm
2. MHR = 220 – 35 = 185 bpm
3. HRR = 185 – 70 = 115 bpm
4. Training zone that will be used: 65-75%
5. Lower end of the training zone:
• 115 x .65 = 75
• 75 + 70 = 145 bpm

6. Upper end of the training zone:
• 115 x .75 = 86
• 86 + 70 = 156 bpm

This information is a fundamental principle for ACE certifications. Knowledge on this subject is required by our professionals.