Heavy Gravity Rooms were special exercise rooms on the Executive Level of the first Death Star where an user could change the level of gravity in the room. Higher settings of gravity meant the user could burn more energy, lose more weight, and build more muscle. It could be dangerous as objects that were heavier could land on a limb and crush toes or break bones.
Conan Antonio Motti used a Heavy Gravity Room on the Death Star during the final stages of its construction. Motti demonstrated to others watching how he could juggle three or four denseplast balls in the heavier environment.