Forget Target Heart Rate When Performing Cardio!

This interesting piece is from my friend, Dr. Gabe Mirkin. It seems that the target heart rate approach to cardio training may be over-rated!  Read on… and be sure to check out Dr.Mirkin’s newsletter http://www.drmirkin.com

When we discuss heart rate training, we often warn against using the ubiquitous formula that says to find maximum HR by subtracting your age in years from 220.

Why? Because if it’s right for you, it’s just dumb luck.

Let’s say you’re 45. Using this formula, your max HR would be 175. But it could actually be anywhere from 164 to 186 (or even outside this broad range) because the formula has a standard deviation of 11.

So if you calculate training zones using the max HR produced by this formula, you’ll very likely be training at intensities too low or too high.

Which begs the question:  How’d this flawed formula come to be?

The interesting answer comes from Gabe Mirkin, M.D., a doc we respect because he’s a lifelong athlete who at 74 still rides 200 miles (322 km) a week. At his website, http://www.drmirkin.com, he specializes in making sense of new medical research that impacts health and athletic performance.

Dr. Mirkin says that “although this 220-minus-age formula is the golden standard used today, it is not based on science.” Here’s why:

“In 1970, a good friend, Sam Fox, was the director of the U.S. Public Health Service program to prevent heart disease. He is one of the most respected heart specialists in the world.

“He and a young researcher were flying to a meeting. They put together several studies comparing maximum heart rate and age.

“Sam Fox took out a pencil and plotted a graph of age verses maximum heart rate and said it looks like maximum heart rate is equal to 220 minus a person’s age.

“A pencil mark has been the accepted formula for nearly 40 years. It has been taught in physical education and heart function courses . . . but the whole concept of maximum heart rate and this formula is ridiculous.”

Dr. Mirkin continues, explaining that for cyclists, “Your legs drive your heart. Your heart does not drive your legs. Maximum heart rate depends on the strength of your legs, not the strength of your heart.

“When you contract your leg muscles, they squeeze against the blood vessels near them to pump blood from your leg veins toward your heart. When your leg muscles relax, your leg veins fill with blood. So your leg muscles pump increased amounts of blood toward your heart.

“This increased blood fills the heart and causes your heart to beat faster and with more force. This is called the Bainbridge Reflex that doctors are taught in their first year of medical school. The stronger your legs are, the more blood they can pump, which causes your heart to beat faster.”

In Dr. Mirkin’s view, you can forget heart rate for training purposes.

Do the following, he says, if you’re in good health and have no heart problems:

“Three times a week, never on consecutive days, either race or push the pace so that you are at your anaerobic threshold and then use bursts to exceed it to become short of breath. On the other four days, take it easy and do not put pressure on your muscles.”

His “anaerobic threshold” is what RBR calls “lactate threshold.” It’s easy to find (although a bit painful). It’s the point where a slight amount of additional effort turns steady deep breathing into shallow panting.

Whatever heart rate this occurs at is the heart rate that really matters when you are seeking serious improvement. No formula needed!

Yours for a Lean Body,
Lee Labrada

Your Lean Body Coach™
Houston, Texa

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