You’ve seen people jogging on the greenway or plodding away on the treadmill, oblivious to all but the ear buds pumping a driving beat into their ears. And, according to science, pumping an extra boost of juice into their workout. The American Council on Exercise recently reviewed seven studies conducted since 1999 that all agreed that listening to music has a positive impact on your workout. (There’s a caveat, but first the facts.)

“Music is like is a legal drug for athletes,” says Costas Karageorghis with from London’s Brunel University School of Sport and Education, who has studied the buff/beat relationship for 20 years. “It can reduce the perception of effort significantly and increase endurance by as much as 15 percent.” Music, Karageorghis has found, tends to distract us and arouse us; it triggers an ingrained instinct that subconsciously drives our bodies to keep pace with the beat. The studies studied involved runners, walkers and cyclists. The studies took different approaches and evaluated on various criteria. But they all showed that a peppier beat leads to a more aggressive, faster workout.

The caveat: You need to pay close attention to the music’s beat. I’m reminded of those junior high dances where you’d ask a girl to dance to a “safe” — meaning fast — beat, only to have the band seamlessly segue into a slow number. Thus, you don’t want want to put your iPod on Shuffle and have your run ricochet from Metallica to Manilow. Or maybe you do, if it’s an interval workout you’re after. Getting the right beat to match your workout is why sites such as ClickMix exist, so you can download just the right bpm (beats per minute) soundtrack to power the workout you have on tap.

Another caveat, albeit more personal preference. I don’t run with music mainly because my run is when I take out the trash in my brain. After a mile or so, the flotsam and jetsam of work begins to drift away. By about mile three, my brain is free to go in whatever direction it chooses. That wouldn’t happen with ABBA rattling around in my head.

If you’re new to the notion of using music to give you an added advantage, the folks at ACE recommend that the beats-per-minute of your music equal the heart rate you hope to achieve during your workout. For instance, if you’ve got a moderate-paced run planned where you expect your heart rate to fluctuate from 145 to 150 beats per minute, ClickMix suggests a mix of, say, Steve Miller’s “Jungle Love” (145 BPM), Heatwave’s “Boogie Nights” (146 BPM), and perhaps some Blondie, “One Way Or Another” (150 bpm).

For more on the study, go here.