Sure your FitBit can count your steps, and Nike+ can track your running progress, but if you’re not measuring your heart rate during cardio exercise, then you might not be getting the best read on the effectiveness of your workout.

Heart rate monitors are so much more than those little metal pads attached to the hand rest on your gym’s elliptical, according to Jimmy Minardi, former pro-athlete and founder of Minardi Training. In fact, you should probably be wearing your heart rate monitor on your body during workouts for the best read.

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“I always have my clients use the chest strap model since I find them most accurate,” Minardi says. “A wireless sensor on the chest strap detects your pulse electronically and sends that data to a wristwatch-style receiver, which displays your heart rate – indicating what percentage of your maximum target heart rate you’ve achieved. Basic models time your workout and give you continuous, average, high and low heart rate data.”

But why track your heart rate at all? Isn’t measuring time and distance enough? Probably not, Minardi says, especially if you’re hoping to build your endurance for high impact cardio, or short bursts of intense exercise.

“When workouts are high intensity and someone’s heart rate isn’t over a specific number of beats per minute depending on their fitness level, I know they’re not reaching their potential,” Minardi says. “But if I see that their heart rate is too high and not coming down quickly at rest, I may have them take a break.”

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Minardi says you also shouldn’t skip the heart rate monitor even if you’re not a gym person and instead prefer trail running or biking. “A heart rate monitor can track your performance during endurance runs whether you’re in the gym or outside,” Minardi says “You can use the information to track and increase exertion to help take your fitness to the next level.”

There’s also no need to drop a ton of cash on pricy models like the $549 IronMan One, unless you’re actually training for an Ironman. Minardi says a good, basic heart rate monitor will do just fine, and will probably only set you back about 70 bucks.

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