The doyenne of aerobic dancing offers an expanded exercise program eliminating some of the problems in her original Aerobic Dancing (1979), and adding some nutrition and stress-reduction tips. The first book featured simple, choreographed routines that, in relatively short periods per day, provided real cardiovascular benefit; the defect was lack of attention to muscular fitness. The new regimens include stretching and strengthening exercises that should overcome those difficulties. Sorensen sets out a 15-minute-a-day program--the ""Everyday Eights""--that works on muscular as well as cardiovascular fitness; in addition, she recommends four strictly aerobic workouts a week (running or swimming, for example--or the dancing patterns that make up the bulk of the guide). With a little advice on nutrition and some characteristic philosophy-of-life (""I've always believed in thinking and dreaming big, and so I readily identify with Barry Manilow's 'Riders to the Stars' ""): a popular regimen that's now more complete and less injury-prone.