Skeletal muscle is not just used to power our movement in three-dimensional space, it is an organ in its own right, responsible for many of the hormones we need to regulate our internal state. The Quick Upperbody Dumbbells Workouts Collection gives you all in one place a handful of super-useful dumbbell workouts you can put into practice the moment you're ready to use an external weight to build strength and muscle. Maintaining muscle mass is one of the anti-ageing strategies employed by those who want to increase their healthspan as well as their lifespan.