In my years studying with Swami Veda Bharati, I was amazed at how he was able to get deep rest by dipping into the state of Yoga Nidra. He was a master of the state.
Yoga Nidra is a state of deep sleep (according to his or her brain waves) with complete conscious awareness. Not only is this state said to be deeply restful and refreshing, but it can also be used for creativity and learning. Swami Veda very rapidly learned to speak English in Yoga Nidra.
If you'd like to learn the preparations for Yoga Nidra, you're in luck, because one of Swami Veda's disciples, Linda Billau, will be teaching a workshop on the subject on July 9. Please see the information on the workshop in the post below.