AN MP3 player that tunes into your heartbeat and matches the tempo. We wore ours on the toilet and it played techno. What the hell does that mean?

Music and exercise are excellent bedfellows. Few things compliment the rush of cardiovascular activity like some motivational music blaring away in your lugholes and filling you with the inspiration to force yourself onwards. Back in the 1940s, keen joggers would employ whole barbershop quartets to accompany them as they pounded across the fields, singing the latest hits of the day in beautiful harmony. The working classes, meanwhile, were forced to beat a simplistic rhythm on their own heads with a lump of wood. It did the trick, but they never got very far.

But ever since the glorious invention of the Walkman, everyone's favourite tunes have been on hand in the great outdoors to help them burn off those cakes. This has led to a fresh quandary - what to listen to? Not every composition suits physical activity, and just as driving needs guitars, relaxation needs pan pipes and sex needs the eerie chanting of Gregorian Monks, so exercise needs something upbeat and lively. Rick Astley or Lisa Stansfield, for example.

In the true spirit of modern gadgetry, technology has stepped in to wrestle even this decision out of your hands. Introducing the Yamaha BODiBEAT, an mp3 player which laughs in the face of conventional grammar. Simply upload a few tunes to the 512mb device, strap it to your wrist, and it will measure your pulse and acceleration and deliver a tune from its memory banks to match it.

Kiss a final farewell to sprinting to Bach, stretching to happy hardcore and wanking to Bob the Builder - your songlist will adjust itself to fit whatever you're doing. If you're really serious about your exercise stats, you can plug your BODiBEAT into a PC post workout and print out a sheet of info to tell you how soon you're going to die, and what of. Ours said "next month, wolves," so we burned it, but yours may be more positive. No, we've misled you, it's just a load of numbers. If you're a fitness mental, that will be the kind of thing that's important to you. You'll be able to get your hands on one sometime this summer.