Are You Working Out Efficiently?

Maximize your workout with a heart-rate monitor.

According to Prevention Magazine, knowing the range of your target heart rate means knowing how to either intensify your workout or maintain a pace that is comfortable but still effective.

"Exercise is like medication," says the magazine's senior fitness editor, Michele Stanton, on The Early Show "You can get an overdose and an under-dose. And by knowing your target heart-rate zone, that can help you get the right dose. (With) a heart-rate monitor, (it) is easy to calculate that."

Here is how you can determine what your target heart-rate zone is:

"A target heart-rate is 60-90 percent of maximum heart rate," notes Stanton. Calculating the target heart-rate zone for CBS News John Roberts who is 47, she explains how to do the math.

First, subtract Roberts' age from 220, which equals 173. Then multiply 173 by .6 to get the lower number in the range: which is 104. Then multiply 173 by .9, to get the higher number in the range: which is 156.

The higher the intensity, the more calories you'll burn. So in this case, Roberts will want to keep his heart rate between 104 and 156 to get a maximum fat burning workout.

"If you're just starting out," Stanton says, "stay toward the lower end. If you've been exercising for a while, bump up the intensity. Try going to the higher end."

Here are few of the heart-rate monitors featured in the August edition of the magazine:

Acumen Eon Basix ES
  • Calorie counter
  • Digital clock and alarm
  • Beeps or flashes when HR is too high or too low
  • Special features: The waterproof design is good for swimmers, kayakers, and rowers.
  • Comments: Tops for beginners. It's the least expensive, and the display panel is easy to read. The monitor doesn't have a lot of extra functions to confuse you.
    Price: $49

    Polar m61
  • Calorie counter
  • Digital clock and alarm
  • Split screen displays time and heart rate (HR)
  • Stopwatch
  • Beeps or flashes when HR is too high or too low
  • Special features: The chest strap is the most flexible and adjustable; it fit snugly even on small-size testers.
  • Comments: Best Splurge
  • This monitor ranked highest for accuracy and fit. Like Cardiosport, the manufacturer recommends sending the watch back to replace the battery.
    Price: $170

    FitSense FS-1
  • Calorie counter
  • Digital clock and alarm
  • Split screen displays time and heart rate (HR)
  • Stopwatch
  • Beeps or flashes when HR is too high or too low
  • Special features: A shoe-mounted device tracks mileage and speed. The watch display can be customized.
  • Comments: Gadget-Lovers' Fave This one has it all. "You can even buy an accessory to download the information to your computer," raved one techy tester.
    Price: $175

    Cardiosport Go 10
  • Digital clock and alarm
  • Split screen displays time and heart rate (HR)
  • Beeps or flashes when HR is too high or too low
  • Special features: Waterproofing lets you swim and row without worry.
  • Comments: Overall Favorite · Its directions were the clearest and most concise. Just one hassle: To replace the watch battery, it's best to send the watch back to the manufacturer.
    Price: $80

    But before you get one, Stanton recommends, "Find something easy to use. Try it before you buy it. You don't want another device that is going to make exercising more difficult. You want it to enhance your workout."
    • Tatiana Morales

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