The oft-repeated saying that we spend a third of our lives asleep is largely true. Sleep helps us recover our energy; it regulates our hormones, allows our body to grow and repair, strengthens our immune system, improves our mental health and, perhaps most ironically for those struggling to sleep, reduces our anxiety.
Energy, liveliness, get-up-and-go, oomph, (or whatever you like to call it) is required for making positive changes to your body, life and world. In the same way that 'like attracts like' in relationships, from a universal perspective, 'life attracts life. Energy attracts energy and what you want is made up of energy.