Do you already work out? It engages the core really well, (make sure you hoop both ways for even muscle development as well! )  But if those muscles are already developed it would definitely feel very easy to you. :) Here's a test done by the American Council  on Exercise! Read and be amazed!  https://www.acefitness.org/certifiednews/images/article/pdfs/HulaHoopStudy.pdf