THE FITNESS studio is filled with laughter and smiles. Giggles do seem a little out of place in a gym, which is usually filled with straining bodies, burning off last night's excesses, but the sound of people having fun is distinct and unmistakable.

The strains of Spanish guitar emanate through the room as the catchy routine, led by professional dancer Caroline Race, is practised and perfected. When the one-hour salsa session eventually comes to an end, some women actually jump up and down and ask, like excited children, to do the dance number "just one more time".

Caroline, who bubbles over with energy, says this session at Bannatyne's Health Club in Darlington is no more or less enthusiastic than any other she teaches at Redworth Hall, near Bishop Auckland. While the sexy Latin-American dance is usually restricted to couples, Caroline has dreamt-up a solo way to put the sauce back into your step. She says it's a deceptively hard workout but that the grind of getting fit is disguised by the fun you have. A captivated audience of passers-by watching her class dance is testimony to how much fun the women inside look like they're having.

"Dance is such a positive way to fitness; as well as giving you an overall workout, it's good for relaxing the mind. I'm very enthusiastic in my classes, which rubs off on everyone who comes," says 28-year-old Caroline, who trained at the North of England College of Dance in Whitley Bay. "If you see these women after a session, you realise how hard they've worked but they tend not to feel like they've been 'working out' because the emphasis is on dance, rather than exercise."

Caroline - who is from Newton Aycliffe, County Durham, and regularly tours the country with the Tina Turner Tribute Show - sings the praises of salsa, not only for its infectious sense of fun but for the amazing toning results on the body. Because you're wiggling, swivelling and twisting, the dance can help achieve the trim hips and flat stomach effect without the need for a single stomach crunch. It's also great for posture as your stance improves and gives you an immense feeling of 'body confidence'.

"You can definitely change your body shape doing a dance like salsa. It gives you both an aerobic and toning workout," says Caroline.

Caroline has always loved dance. From the moment she was sent to her first ballet class at the age of five, she knew it was going to be her life's vocation. Ironically, she picked up salsa while she was working out in Greece as a fitness instructor. She liked the idea of transforming the liberating, sensual dance into a solo routine because she felt dancing in pairs might keep many away.

"It's awkward for some people to come to a class without a partner or to dance with a stranger, so I thought it would be more appealing this way, says Caroline. "Dancing is the perfect way to unwind and work your body if you don't like to do a gym routine. And it's a way of letting go of inhibitions and losing yourself in the music. You can really feel free and let your hips swing. It's very sexy to do solo salsa."