The science of workout music

You're bundling up for a chilly morning run. Or about to climb on the elliptical for a high-energy workout. Or warming up before a weightlifting session.

What's the first thing you reach for?

Your earbuds, naturally.

Studies have shown that listening to music that fits the cadence of what you're doing - running, cycling, aerobics - makes you work harder.

"The metronome aspect, the synchronization of movement to music, is the most important," says Carl Foster, director of the Human Performance Laboratory at the University of Wisconsin at Lacrosse.

The idea of synchronizing movement to a beat is nothing new, he points out: In Roman galleys, the drumbeat drove the pace of the rowers. "But there is also the distraction and arousal that music brings," Foster says. They both matter, but it's unclear how much. "There's definitely more buried in music that affects us. But we don't know exactly how to tease it out."

So, how to pick the "right" music?

If you want to make a workout mix based on tempo - or BPM, for beats per minute - various websites, including www.songbpm.com, can help you determine the tempo of your favorite music to see whether it fits your intended activity. Or you can go to sites such as www.motiontraxx.com that offer playlists at a certain BPM for running and cycling as well as other activities. Other sites include www.workoutmusic.com and www.powermusic.com.

"Music is positive energy," says Deekron "the Fitness DJ" Krikorian, who produces fitness playlists for MotionTraxx. "So when I put together playlists, I look for intensity, positive feeling and cohesiveness."

If he finds a song that feels right in terms of mood and intensity but has the wrong tempo, he might manipulate the BPM to fit the type of exercise intended.

"The beat becomes very important anytime there is repetitive movement," Krikorian says. "Our instincts tell us to move to the beat. Our feet tell us to move to the beat."

The ideal cadence for running is a hotly debated topic in the running world, and variations in stride length mean finding your ideal tempo could take a bit of experimentation. Some sources say an eight-minute mile corresponds with a BPM of 170; others go up to 200. Some suggest the ideal running cadence is in the 170s to 180s. And some studies show that faster may be better for injury prevention.

If that sounds like too much work, try a group fitness class; cycling, step and aerobics instructors have been leveraging the power of the beat for years.

Ingrid Nelson, a cycling instructor who packs her tempo-driven classes at Washington's Biker Barre, says intensity, style and cadence are all important when putting together her playlists.

"I like a lot of '90s hip-hop and usually stay in the range of 95 to 105 BPM," Nelson says, aligning the beat to the cyclers' revolutions per minute. But she might go as low as 80 or as high as 120 BPM for hills and sprints, respectively. When drills are aligned with the beat, she says, participants "connect with music" and "relax into the pulse."

As for other fitness activities such as step aerobics, the tempo hovers around 130 BPM, says Harold Sanco, group fitness director and instructor at Results gym in Washington. "You have to pick music that is both safe and effective," he says. "If you are going too fast, you risk injury and you're not working out effectively because you are not getting the full range of motion."

Boston is a fitness trainer and freelance writer. She can be found at www.gabriellaboston.com.