When dance instructor Carol Hensel recorded an exercise-to-music album last fall she never expected to sit atop the record-industry charts along with Dolly Parton, Marvin Gaye and Kool & the Gang.

But "Dancersize" has been climbing the top-selling album charts for the past 12 weeks and currently is No. 53 on the list complied by Cash Box, a record-industry trade publication.

"People love to dancersize because you can work out without wearing out," says Hensel, 27, who holds a degree in dance and was teaching dancersize classes at the Akron, Ohio, YMCA when selected to cut the album.

"It's amazing how many sit-ups you can do without realizing it when you've got inspiring music like 'I Love You Just The Way You Are' or 'I Will Survive' behind you. With the record you can dancersize in the privacy on your home."

The album was the idea of Joey Porrello, president of Our Gang Entertainment Inc. record-production company, who claims "Dancersize" is the first exercise album to hit the big music charts.

"My wife was taking an aerobic-type dance class," he says, "and she was always coming home, putting on pop records and dancing. One day I was watching her dance and, almost simultaneously, I looked at her and she looked at me and we said, together, 'We should do an album.'"