MILO BRYANT: 3 ways to find your target heart rate

Last week, we began discussing heart-rate training. Now that we’ve established it to be a methodical and scientific way of improving cardiovascular fitness, we need to apply the science.

To find our target heart-rate zones, we have to find our heartrate maximum, and doing that is a bit tricky if we want to get the most accurate number.

In reality, it’s almost impossible to get a definitive number because of factors including altitude, heat, caffeine intake, illness, age, gender, etc.

The best we can do is approximate. Here are several ways.

1. The Karvonen Formula is a popular method because it’s free. It uses the target heart rate, or THR, as a percentage of the maximum heart rate, or MHR, while factoring in the resting heart rate, or RHR. Start off by subtracting two-thirds of your age from 206.9, a number established as a starting point. Take that result and subtract your resting heart rate. Then take that number and multiply it by 55 percent and again by 85 percent. Then, add your RHR to each of those numbers to get your target heart-rate zone.

Here’s an example using a 37-year-old with an RHR of 56:

- 206.9 - (.67 x 37 (age)) = 182.

- 126 x .55 (middle of recovery zone) = 69.3; AND 126 x .85 (middle of anaerobic zone) = 107.1.

- 69.3 + 56 = 125.3; 107.1 + 56 = 163.1.

So, this person’s target heartrate zone is from 125 to 163 heartbeats per minute.

Critics of this formula say the results could be off by up to nine beats per minute — too big a discrepancy for elite athletes.

2. VO2 max testing is the most accurate way I know of to find your THR zone. Our fitness level can be measured by the amount of oxygen we take in while exercising with maximum effort. The better shape we’re in, the higher our VO2 max.

But these tests cost $125 to $200 and have to be administered by a specialist. Because we get in better cardiovascular conditioning as we progress, we need to recalculate our THR zones every couple of months. That can get expensive.

3. A 30-minute field test with a heart-rate monitor might be the best way to go. But the monitor can range from $75 to $400. After that, though, the only cost is 30 minutes of your time for a jog.

Hit the lap button on the heartrate monitor at the 10-minute and 20-minute marks, and stop the test after 30 minutes. Take the average heart rate between the 20-minute and 30-minute marks to establish the THR zones. If the average is 175, your zone is a percentage of that. The 60 to 70 percent zone is suffcient for increasing cardiovascular conditioning for most.

You can get more information from the following books, but they’re not for the absolute beginner: “Total Heart Rate Training," by Joel Friel; "Precision Heart Rate Training," by Edmund Burke; and "Heart Zone Training," by Sally Edwards.

Milo Bryant has two National Strength and Conditioning Association certifications and he appears on KOAA's Comcast Channel 9 most Wednesdays at 4 p.m. You can contact him by e-mail at milo.bryant@ gazette.com or read his blog at milobryant.blogspot.com.