The crossword solution for the term 'Aerobics Class Reminder' is ACHE, which is a four-letter word. ACHE is a common word used to describe a dull, continuous pain or a feeling of discomfort. It is often associated with physical pain, but it can also be used to describe emotional pain. ACHE is often used to remind people of the importance of taking care of their bodies and minds, which is why it is an appropriate solution for the term 'Aerobics Class Reminder'.