Monday, May 01, 2006

Cardio Workouts: How Intense Should They Be?

First off, I like to hike in the hills and woods. Treadmills and stationary bikes are mostly for stormy days, as far as I’m concerned. What I can’t imagine is being on a wonderful trail in the hills, then stopping, locating my pulse (to be accurate, you’re supposed to do it within 5 seconds of stopping), counting the beats, multiplying, etc. Nonsense. Won’t do it.

For me, the “talk test” works just fine. You probably know how it works: Once you are warmed up and have worked up a little sweat, try to speak in short sentences. Utterances of just a few words. If you can do it without gasping for air, you are at about the right pace. On the other hand, if you can talk on and on while not even breathing hard, you are taking it too easy. So pick up the pace.

Yes, it’s subjective. Yet it’s pretty reliable and, most of all, doesn’t intrude on the outdoor experience.

For a little more precision, there are all sorts pulse rate monitoring devices you wear like a wristwatch. And I certainly have nothing against them, since a quick glance at a monitor isn’t much of an interruption.

Of course, even convenient heart monitors can be misused. A man came to a cardio-kickboxing class I was teaching and kept stopping during the workout to read his monitor. I guess he was obsessed with precision because he would come to a halt every few minutes.

After the class, I asked him if he liked the workout. He said he did but was a little disappointed that he didn’t get his heart rate high enough. Gee, I wonder why?

When I use a gym treadmill, I do appreciate the newfangled heart monitors where you just grip the handrails for a few seconds as you run. And boom! There is your heart rate right there on the screen. No stopping for pesky calculations. Pretty neat. I’m not a complete Luddite after all.

Lets get to it. What should one’s heart rate be during an effective cardio session? Here are two ways to figure it:

The Standard Method (most commonly used):

• Take the number 220 and subtract your age from it. That is your Maximum Heart Rate (MHR). Do not exercise at or near your Maximum Heart Rate.

• Exercise instead at your Target Heart Rate (THR), which should be between 60% and 90% of your (MHR).

• Beginners’ Target Heart Rates (THR’s) should be in the 60% to 70% range. Intermediates, 70% to 80%. And advanced exercisers, 80% to 90%.

• Do not go above 90% for sustained periods.

• To increase your aerobic capacity, train at least 3 times per week, and approximately 4 to 6 weeks in a category, before moving up to the next level.

The Karvonen Formula (considered more precise than the Standard Method):

• Determine your resting heart rate (RHR) by measuring it before getting out of bed in the morning. Count your heartbeats for 10-seconds and multiply by 6. That is your resting heartbeat. (As your cardiovascular system becomes stronger, your resting heartbeat will become lower. So you will need to repeat the measurement.)

• Now determine your Maximum Heart Rate (MHR): Subtract your age from 220. That is your MHR.

• Subtract your resting heart rate (RHR) from your maximum heart rate (MHR).

• Multiply that figure by the intensity percentage you want (between 50% and 85%).

• Add your resting heart rate (RHR) to that figure.

• That is your Target Heart Rate (THR) using the Karvonen Formula.

Or, if you’d rather not mess with the math, click here. Enter your age and resting heart rate and, like magic, the computer does it for you.

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