Water fitness classes are a type of exercise class that takes place in a pool. Participants use the resistance of the water to help them build strength and improve their cardiovascular health. The classes often involve a combination of aerobic exercises, stretching, and strength training. The term 'POTABLE' is used to describe water that is safe for drinking. Therefore, the term 'water fitness class' can be used to describe a class that takes place in a pool with POTABLE water.