Dumbbells are inexpensive‎,‎‎ versatile and easy‎-to‎‎-use weights that let you create a variety of workouts to improve your health‎.‎‎ Depending on the amount of weight you use‎,‎‎ number of repetitions you do and pace at which you use them‎,‎‎ dumbbells can help you improve cardiovascular fitness‎,‎‎ burn calories‎,‎‎ build muscle or increase muscular endurance for sports‎.‎ Dumbbells are small weights‎‎,‎‎ shaped like a Roman letter I‎‎,‎‎ resembling mini‎,‎‎ single‎-piece barbells‎.‎‎ You purchase dumbbells in different weights‎,‎‎ starting with lightweight versions ‎‎-‎‎- less than 3 KG ‎‎-‎‎- to use during aerobic workouts or while using a treadmill or exercise bike‎.‎‎ Heavier dumbbells let you body build‎.‎