Gorgasm (1990)

Two sniveling high school dropouts plot to rob the school janitor and accidentally release toxic chemicals into the school's water supply. The swimming team are the first ones to turn into green-faced flesh-eating zombies, and they promptly go after the rest of the present school populace: two horror movie nerds, the members of a metal band and the world's worst basketball team.

After a nice shower, Linnea does some warm-up stretches and then goes for a run. She encounters some flabby zombies who follow her back to the house, where she leads them in some poolside aerobic routines. Later she unwinds by inviting some girlfriends over for a slumber party and some exercise. When something goes bump in the house, her friends begin experiencing an attrition problem.

Police detective, Mitchell, investigating the death of a victim of a Nazi concentration camp discovers a nightclubbing playboy who has strange powers over women and is seemingly ageless.