Go to your local fitness center and it’s likely you’ll hear all kinds of music, from the thump-thump beats of the step-aerobics classes, to the heart-pounding rhythms emanating from the spinning classes, to Metallica screaming from the headphones of the guys banging the free-weights around. People instinctively use music to help them with their workouts, and it turns out there’s plenty of scientific evidence to back the practice up.

In fact, UK researcher Dr Costas Karageorghis, of Brunel University recently published a study that shows that using the right music before and during a workout can boost your performance by as much as 20 percent. But “the right music” is a matter of individual taste. Karageorghis says, “Our recent research shows that there’s no definitive play list for today’s gym-goers or tomorrow’s sporting heroes… it’s up to the individual to select songs that drive them and inspire them.”

But maybe not so much adagios unless you’re looking to chill out.

Dr. Karageorghis has been studying the effects of music on exercise performance for over 20 years, following one of those niche career paths few find their way to. In one of his latest studies, 12 male college students rode stationary bicycles for half an hour while listening to music through headphones. Unknown to them, the researchers slowed down the pace of the song by 10 percent for part of the ride, and speeded it up by 10 percent at other points. As expected, when the music slowed, so did riding speed and distance covered. When the music went faster, so did the rider.

Another 2009 study found that basketball players who had poor performance during high-pressure games did significantly better if they listened to Monty Python’s “Always Look on the Bright Side of Life” before going out onto the court. The researchers theorize that the effect works because the lighthearted music distracts mental attention while simultaneously sparking the heart to pump faster and breathing rate to increase.

The preponderance of recent studies might have amused the ancient Greeks, who instinctively knew that music gets the testosterone pumping, “We know the Greeks went into battle listening to music in the Dorian mode,” says Bill Conti, composer of the “Rocky Theme Song,” (long a favorite to inspire marathon runners). “I can only imagine some Greek guy said, ‘This works.'” And, of course, for hundreds of years the Scots have marched into battle accompanied by the music of the pipes.

But today’s researchers not only want to verify that music works to boost performance; they also want to determine exactly what typeof music works best, down to frequency and beat. Dr. Karagerghis says that fast-tempo music works best for high-intensity exercise and slower beats work well for cool-down. (Well, I guess you can use an adagio after all.) The loud, driving beats inspire athletes before performance, while slower, soothing rhythms calm them down. Ultimately, what works depends on the individual. “Rather than blasting out the same music loudly in all areas of the gym, it would be better to turn the volume down so those on the treadmills and bicycles can tune into personal music selections,” says Dr. Karagerghis, “while those in weight training rooms can hear the uplifting beat of the background music,” he said.

Much more is known about how music boosts performance than about ‘why.’ According to Dr. Karageorghis, “Music is like is a legal drug for athletes. It can reduce the perception of effort significantly and increase endurance.” Studies have shown that music distracts the mind from discomfort or difficulty while sparking the heart and muscles. It may well be that the nervous system somehow synchs with the music and beat before the mind even has a chance to “get jiggy with it.”

And tempo or beat may be the real secret to the effect. Carl Foster, Ph.D., of the University of Wisconsin, La Crosse, Exercise and Health Program says, “You go all the way back to rowers on the Roman galleys. The guy is sitting there beating on his drum and he drives the basic rhythm of the rowing. Part of that is coordination — you want the rowers to row together — but part of it is that people will naturally follow a tempo.”

Runners, for example, seem to benefit from matching their stride-rate to music with a pace — measured in beats per minute (BPM) — that is at the same speed or higher. In fact, there are music-training programs that aim to match a runner’s stride with the BPM by choosing particular songs. The song, Gettin’ Jiggy With It,” by Will Smith has a BPM of 108, making it a good warm-up choice. “Rockafeller Skank (Funk Soul Brother,)” by Fatboy Slim, on the other hand, has a BPM of 153, making it great for building endurance. To warm down or get mentally prepared, slower beats, like “Whatta Man” by Salt-n-Pepa, at 89 BPM, work well. You don’t have to do high-tech calculations to figure out what music you should download into your Ipod for your workout. In fact, numerous websites offer workout music with the math already calculated. Check out Hella Sound for a 30-minute workout tape with various paced-versions of the same song for building running speed. For marathon training, try Audio Performance Team, which advertises “marathon training with music at 180 steps per minute.”

If none of these options appeals to you, just play your own favorite music to inspire you before you work out, while you work out, and afterwards, so you remember your workout as being a pleasant experience and feel inspiration to do it again.

There is, however, one caveat when it comes to listening to music while exercising: you need to exercise caution. Music can be distracting, and if you’re wearing ear buds, it may leave you vulnerable to approaching danger such as traffic if you’re out cycling.

::hc