THE QUESTION

I am 57 years old. I have always been told to use the "220 minus age" formula to measure my maximum heart rate and corresponding appropriate heart-rate zones. Is this the best formula for me to use?

The "220-age" formula is a simple and easy to remember guideline for figuring out heart-rate zones, but by no means is it the ultimate test. It is not 100 per cent accurate because the only fitness indicator it takes into account is age.

Try the Karvonen method. It is a more accurate formula because it takes both age and resting heart rate into account.

Step 1. Manually measure your resting heart rate. Take your pulse for 15 seconds and then multiply that number by four.

Let's say that your resting heart rate is 60. We know your age is 57.

Step 2. Find your age-predicted max heart rate: 220 minus age (57) = 163

Step 3. Find your heart-rate reserve (HRR). Max heart rate (163) minus resting heart rate (60) = 103

Step 4. Find 60 per cent of max heart rate. (103 multiplied by .6) plus resting heart rate (60) = 121.8 beats per minute (bpm)

Step 5. Find 80 per cent of max heart rate. (103 multiplied by .8) plus resting heart rate (60) = 142.40

According to the Karvonen formula, you should keep your heart rate between 122 and 142 bpm.

Using the "220-age" formula, your heart-rate zone would be 98 to 130 bpm.

Trainer's Tip: If you currently use the 220 minus age formula, try completing the above equation with your own age and resting heart rate and compare the results with what you would get with the Karvonen formula. As you can see, the numbers can be quite different.

Send certified personal trainer Kathleen Trotter your questions at trainer@globeandmail.com . She will answer select questions, which could appear in The Globe and Mail and/or on The Globe and Mail web site. Your name will not be published if your question is chosen.

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