Sunday, May 25, 2008

The Skinny on Heart Rates, Part 1

A coulple of years ago, at about the same time I began to study and learn about training intensity, I bought a heart rate monitor. I bought a Polar brand, model F11. The particular model consisted of a wrist watch and a chest strap. It works with a transmitter resting on your chest sending a signal to the wrist watch. The resulting readout is how many times your heart is beating per minute....simple enough.

Monitors like these are an easy, comfortable way to get real-time information about your heart's performance during a workout. The old standard of finding your pulse and counting the beats while you watch a second hand on a clock is not nearly as accurate (as your body begins to rest during the exam period, your heart rate falls giving an inaccurate reading...not to mention temporary loss of workout time and intensity).

Here are some watered-down basics of heart rate study:

HR-Max = 220 minus your age OR 205.8 minus (0.685 times your age). Either is an estimate for a number that should be determined by a professional stress test. And because I too love doctors (NOT!), I use 200 minus age ;)

HR-Resting = your heart rate while resting...duh! I usually take mine before I get out of bed in the morning, and definately before I take the morning cup of joe. The average value for an adult is about 70 to 90 beats per minute (BPM).

HR Reserve = (abbreviated HRR) the number of beats between your HR-Max and HR-Resting. Just subtract the two values.

HR-Target = (abbreviated THR) or a value of BPM that matches up with an intensity level of a particular workload. This is math formula with variables from 1-100, 1=resting and 100=max.

Various intensity levels based on heart rate are important to know. After you know the values, use them as target heart rates. Using a THR model gives a more efficient workout with less time wasted to reach set goals. Now let's use a case study to determine some intensity levels.

Subject is a 30yoa male with a HR-Resting of 50BPM. His HR-Max is 190 (=220-30). His HRR is 140 beats (=190-50). Now a 50% intensity workout means his heart is beating at 1/2 its ability (or using half of the 140 reserve or "extra beats"). Take 140 and multiply by 0.5 to get 70. Then add this to the HR-Resting to get a 50% intensity value of 120BPM. To find an 85% intensity value, multiply 0.85 and 140 to get 119, plus 50, equals 169BPM. Now since reaching and maintaining a THR exactly on the number is virtually impossible, THR Zone are commonly used. For example, 50-60% zone or a 75-85% zone.

This is enough math for now. Figure out your values for HR-Max, HR-Rest, HRR, and THR for 50, 60, 70, and 80% intensities. We'll get back to these numbers in Part 2.

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